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- 501. J. Appl. Phys. 99, 053516 (2006) , “Correlation between Zn vacancies and photoluminescence emission in ZnO films”, A. Zubiaga, J. A. García, F. Plazaola, F. Tuomisto, K. Saarinen, J. Zuñiga Pérez, and V. Muñoz-SanjoséPhotoluminescence and positron annihilation spectroscopy have been used to characterize and identify vacancy-type defects produced in ZnO films grown on sapphire by metal-organic chemical-vapor deposition. The photoluminescence of the samples in the near band edge region has been studied, paying... (Read more)
- 502. J. Appl. Phys. 99, 053502 (2006) , “Spectroscopic analysis of defects in chlorine doped polycrystalline CdTe”, V. Consonni, G. Feuillet, and S. RenetThe effects of Cl doping of thick polycrystalline CdTe layers grown by close space sublimation on their crystalline structure and the compensation and passivation processes have been investigated. From an extensive low temperature photoluminescence study, it is shown that, in polycrystalline... (Read more)
- 503. J. Appl. Phys. 99, 044105 (2006) , “Passivation of oxygen vacancy states in HfO2 by nitrogen”, K. Xiong, J. Robertson, and S. J. ClarkNitrogen is known to reduce leakage currents and charge trapping in high-dielectric-constant gate oxides such as HfO2. We show that this occurs because nitrogen, substituting for oxygen atoms next to oxygen vacancy sites, repels the occupied gap states due to the neutral and positively... (Read more)
- 504. J. Appl. Phys. 99, 043509 (2006) , “Influence of metal trapping on the shape of cavities induced by high energy He+ implantation”, R. El Bouayadi, G. Regula, M. Lancin, B. Pichaud, and M. DesvignesIn He implantation induced cavities highly contaminated with metals (Au, Ni, Pt) we found that, when no three-dimensional structure is observed, the shape of the cavities can be strongly modified depending on the nature of the metal and on its trapped quantity. The equilibrium shape of cavities is... (Read more)
- 505. J. Appl. Phys. 99, 033701 (2006) , “Diffusion length and junction spectroscopy analysis of low-temperature annealing of electron irradiation-induced deep levels in 4H-SiC”, A. Castaldini, A. Cavallini, L. Rigutti, S. Pizzini, A. Le Donne, and S. BinettiThe effects of low-temperature annealing in 8.2 MeV electron-irradiated 4H-SiC Schottky diodes were investigated. Deep-level transient spectroscopy and minority-carrier diffusion length (Ld) measurements were carried out on not-irradiated samples and on irradiated... (Read more)
- 506. J. Appl. Phys. 99, 023702 (2006) , “Deep traps in oxide-nitride-oxide stacks fabricated from hydrogen and deuterium containing precursors”, G. Rosenman, M. Naich, Ya. Roizin, and Rob van SchaijkThe energy spectrum of the traps and thermal stability of stored charge have been studied by the thermostimulated exoelectron emission method in hydrogenated H and deuterated D oxide-nitride-oxide (ONO) multilayer stacks of silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memories. It is... (Read more)
- 507. J. Appl. Phys. 99, 023523 (2006) , “Characterization of 6H-SiC surfaces after ion implantation and annealing using positron annihilation spectroscopy and atomic force microscopy”, G. Brauer, W. Anwand, W. Skorupa, S. Brandstetter, and C. TeichertSystematic slow positron implantation spectroscopy (SPIS) and atomic force microscopy studies of various 6H-SiC samples are presented to clarify the role of conductivity type, crystal quality, ion implantation (B+,Al+, and N+), and annealing (1.650 °C) in... (Read more)
- 508. J. Appl. Phys. 99, 013701 (2006) , “Electronically activated boron-oxygen-related recombination centers in crystalline silicon”, Karsten Bothe and Jan SchmidtTwo different boron- and oxygen-related recombination centers are found to be activated in crystalline silicon under illumination or electron injection in the dark, both leading to a severe degradation in the carrier lifetime. While one center forms on a time scale of seconds to minutes, the... (Read more)
- 509. J. Appl. Phys. 99, 013515 (2006) , “Defects and electrical behavior in 1 MeV Si+-ion-irradiated 4H–SiC Schottky diodes”, F. Roccaforte, S. Libertino, V. Raineri, A. Ruggiero, V. Massimino, and L. CalcagnoIn this paper, the formation and evolution of defects induced by ion irradiation with 1 MeV Si+ ions in Ni2Si/4HSiC Schottky diodes were studied and correlated with the electrical properties of the contacts. The current-voltage characteristics of the contacts... (Read more)
- 510. J. Appl. Phys. 99, 013508 (2006) , “Residual impurities and native defects in 6H-SiC bulk crystals grown by halide chemical-vapor deposition”, S. W. Huh, H. J. Chung, S. Nigam, A. Y. Polyakov, Q. Li, M. Skowronski, E. R. Glaser, W. E. Carlos, B. V. Shanabrook, M. A. Fanton, and N. B. SmirnovA variety of defect-sensitive techniques have been employed to detect, identify, and quantify the residual impurities and native defects in high-purity (undoped) 6H-SiC crystals grown by halide chemical-vapor deposition technique. The incorporation efficiencies of N and B are determined by... (Read more)
- 511. J. Appl. Phys. 99, 013502 (2006) , “Luminescence of bound excitons in epitaxial ZnO thin films grown by plasma-assisted molecular beam epitaxy”, Y. S. Jung, W. K. Choi, O. V. Kononenko, and G. N. PaninLuminescence properties of ZnO films, which have been epitaxially grown on c-sapphire (0001) substrates by plasma-assisted molecular beam epitaxy, are investigated by means of different excitation sources and their measurement conditions. With the increase of measurement temperature,... (Read more)
- 512. J. Appl. Phys. 99, 011101 (2006) , “Degradation of hexagonal silicon-carbide-based bipolar devices”, M. Skowronski and S. HaOnly a few years ago, an account of degradation of silicon carbide high-voltage p-i-n diodes was presented at the European Conference on Silicon Carbide and Related Compounds (Kloster Banz, Germany, 2000). This report was followed by the intense effort of multiple groups... (Read more)
- 513. J. Phys. Chem. Solids 67, 789 (2006) , “Spectroscopic and magnetic studies of manganese ions in ZnO–Sb2O3–B2O3 glass system”, M. Srinivasa Reddy, G. Murali Krishna , N. VeeraiahZnO–Sb2O3–B2O3 glasses containing different concentrations of MnO ranging from 0 to 1.0 mol% were prepared. A number of studies, viz. optical absorption, infrared and ESR spectra and magnetic susceptibility, were carried out as a function of manganese ion concentration. The analysis of... (Read more)
- 514. J. Phys.: Condens. Matter 18, L551 (2006) , IOP Publishing , “Observation of a new high-pressure semimetal phase of GaAs from pressure dependence of the thermopower”, S.V. Ovsyannikov, V.V. ShchennikovWe report the use of the thermopower technique (Seebeck effect) as an effective tool for discovery of 'hidden' (for standard techniques, like x-ray, synchrotron, Raman, etc) phases of substances. Applying the thermopower technique to a set of GaAs single crystals pressurized in a sintered diamond... (Read more)
- 515. Jpn. J. Appl. Phys. 45, L991 (2006) , “Lowering the Switching Current of Resistance Random Access Memory Using a Hetero Junction Structure Consisting of Transition Metal Oxides”, Kentaro Kinoshita, Tetsuro Tamura, Masaki Aoki, Yoshihiro Sugiyama and Hitoshi TanakaBoth lowering the “reset” current of resistance random access memory (ReRAM) and raising the resistance in the low resistance state are crucial for practical use of ReRAM. These requirements have been satisfied by using a hetero junction structure consisting of transition metal oxides, NiOy/TiOx/Pt, combining direct contact with the NiOy using a W-probe. It is considered that this configuration brought about extreme downsizing of the effective area of both the top and bottom electrodes for NiOy and thus decreased the number of filaments formed in “forming” process. Reducing the number of filaments is essential to these issues. (Read more)
- 516. Mater. Sci. Eng. B 126, 222-225 (2006) , “Magnetic properties of a new spintronic material—GaN:Fe”, H. Przybylińska, A. Wolos, M. Kiecana, M. Sawicki, T. Dietl, H. Malissa, C. Simbrunner, M. Wegscheider, H. Sitter, K. Rumpf, P. Granitzer, H. Krenn and W. JantschWe report on metal-organic chemical vapour deposition growth of GaN:Fe and its characterization by means of high-resolution X-ray diffraction, secondary ion mass spectroscopy, electron spin resonance, and magnetization measurements. Electron spin resonance studies demonstrate the existence of Fe in... (Read more)
- 517. Microelectron. Reliability 46, 1 (2006) , “NBTI degradation: From physical mechanisms to modelling”,An overview of the evolution of transistor parameters under negative bias temperature instability stress conditions commonly observed in p-MOSFETs in recent technologies is presented. The physical mechanisms of the degradation as well as the different defects involved have been discussed according to a systematic set of experiments with different stress conditions. According to our findings, a physical model is proposed which could be used to more accurately predict the transistor degradation. Finally, based on our new present understanding, a new characterization methodology is proposed, which would open the way to a more accurate determination of parameter shifts and thus allowing implementing the degradation into design rules. (Read more)
- 518. Nature 442, 436 (2006) , “Atom-by-atom substitution of Mn in GaAs and visualization of their hole-mediated interactions”, D. Kitchen, A. Richardella, J. -M. Tang, M. E. Flatt, A. YazdaniThe discovery of ferromagnetism in Mn-doped GaAs1 has ignited interest in the development of semiconductor technologies based on electron spin and has led to several proof-of-concept spintronic devices2, 3, 4. A major hurdle for realistic applications of Ga1-XMnXAs, or other dilute magnetic semiconductors, remains that their ferromagnetic transition temperature is below room temperature. Enhancing ferromagnetism in semiconductors requires us to understand the mechanisms for interaction between magnetic dopants, such as Mn, and identify the circumstances in which ferromagnetic interactions are maximized5. Here we describe an atom-by-atom substitution technique using a scanning tunnelling microscope (STM) and apply it to perform a controlled study at the atomic scale of the interactions between isolated Mn acceptors, which are mediated by holes in GaAs. High-resolution STM measurements are used to visualize the GaAs electronic states that participate in the Mn–Mn interaction and to quantify the interaction strengths as a function of relative position and orientation. Our experimental findings, which can be explained using tight-binding model calculations, reveal a strong dependence of ferromagnetic interaction on crystallographic orientation. This anisotropic interaction can potentially be exploited by growing oriented Ga1-XMnXAs structures to enhance the ferromagnetic transition temperature beyond that achieved in randomly doped samples. (Read more)
- 519. Phys. Rev. B 74, 245420 (2006) , “Energetics, structure, and long-range interaction of vacancy-type defects in carbon nanotubes: Atomistic simulations”, J. Kotakoski, A. V. Krasheninnikov,, and K. NordlundThe presence of vacancy clusters in carbon nanotubes has been assumed to explain the formation of carbon peapods and the difference between the experimentally measured and theoretical fracture strength of nanotubes. We use atomistic simulations at various levels of theory to study the... (Read more)
- 520. Phys. Rev. B 74, 245411 (2006) , “Vacancy defects and the formation of local haeckelite structures in graphene from tight-binding molecular dynamics”, Gun-Do Lee, C. Z. Wang, Euijoon Yoon, Nong-Moon Hwang, and K. M. HoThe dynamics of multivacancy defects in a graphene layer is investigated by tight-binding molecular dynamics simulations and by first principles calculation. The simulations show that four single vacancies in the graphene layer first coalesce into two double vacancies, each consisting of a... (Read more)
- 521. Phys. Rev. B 74, 245219 (2006) , “Dynamics of positively charged muonium centers in indium nitride”, Y. G. Celebi, R. L. Lichti, B. E. Coss, and S. F. J. CoxMuon spin depolarization measurements performed on powdered InN with zero applied magnetic field reveal several positively charged diamagnetic muonium centers. At low temperatures, the Mu+ ground state is weakly relaxing with the characteristics of local tunneling motion, which changes to... (Read more)
- 522. Phys. Rev. B 74, 245217 (2006) , “Donor levels for selected n-type dopants in diamond: A computational study of the effect of supercell size”, J. P. Goss, P. R. Briddon, and R. J. EyreComputational techniques are key predictive tools in the drive to engineer semiconductive materials. Diamond, intrinsically a wide band-gap insulator, can be made to semiconduct n-type by doping with phosphorus. However, the relatively deep level at Ec−0.6 eV... (Read more)
- 523. Phys. Rev. B 74, 245216 (2006) , “Influence of excited states of a deep substitutional dopant on majority-carrier concentration in semiconductors”, Hideharu MatsuuraThe density (NA) and energy level (EA) of an acceptor in a p-type wide-band-gap semiconductor (e.g., SiC, GaN, and diamond) are determined by a least-squares fit of the charge neutrality equation to the temperature dependence of the hole... (Read more)
- 524. Phys. Rev. B 74, 245212 (2006) , “Deactivation of nitrogen donors in silicon carbide”, F. Schmid, S. A. Reshanov, H. B. Weber, G. Pensl, M. Bockstedte, A. Mattausch, O. Pankratov, T. Ohshima, and H. ItohHexagonal SiC is either co-implanted with silicon (Si+), carbon (C+), or neon (Ne+) ions along with nitrogen (N+) ions or irradiated with electrons (e−) of 200 keV energy. During the subsequent annealing step at temperatures above 1450 ... (Read more)
- 525. Phys. Rev. B 74, 245205 (2006) , “Mn incorporation in as-grown and annealed (Ga,Mn)As layers studied by x-ray diffraction and standing-wave fluorescence”, V. Holý, Z. Matj, O. Pacherová, V. Novák, M. Cukr, K. Olejník, and T. JungwirthA combination of high-resolution x-ray diffraction and a technique of x-ray standing-wave fluorescence at grazing incidence is employed to study the structure of a (Ga,Mn)As-diluted magnetic semiconductor and its changes during post-growth annealing steps. We find that the film is formed by a... (Read more)
- 526. Phys. Rev. B 74, 245203 (2006) , “Diffusion and conversion dynamics for neutral muonium in aluminum nitride”, H. N. Bani-Salameh, R. L. Lichti, Y. G. Celebi, and S. F. J. CoxMuon spin depolarization rates and hyperfine decoupling curves imply the existence of a neutral muonium center to high temperatures in AlN, providing an experimental model for interstitial atomic hydrogen. This center has a hyperfine interaction close to that of the free atom, but with a small... (Read more)
- 527. Phys. Rev. B 74, 245201 (2006) , “Electrical resistivity and metal-nonmetal transition in n-type doped 4H-SiC”, Antonio Ferreira da Silva, Julien Pernot, Sylvie Contreras, Bo E. Sernelius, Clas Persson, and Jean CamasselThe electrical resistivity of 4H-SiC doped with nitrogen is analyzed in the temperature range 10–700 K for nitrogen concentrations between 3.5×1015 and 5×1019 cm−3. For the highest doped samples, a good agreement is found between the... (Read more)
- 528. Phys. Rev. B 74, 241303(R) (2006) , “Enhancement of interactions between magnetic ions in semiconductors due to declustering”, A. Franceschetti, S. V. Barabash, J. Osorio-Guillen, A. Zunger, and M. van SchilfgaardeIt is often assumed that the exchange interaction between two magnetic ions in a semiconductor host depends only on the distance and orientation of the magnetic ions. Using first-principles electronic structure calculations of Mn impurities in GaAs, we show that the exchange interaction between two... (Read more)
- 529. Phys. Rev. B 74, 235434 (2006) , “Transport properties of n-type ultrananocrystalline diamond films”, I. S. Beloborodov, P. Zapol, D. M. Gruen, and L. A. CurtissWe investigate transport properties of ultrananocrystalline diamond films for a broad range of temperatures. Addition of nitrogen during plasma-assisted growth increases the conductivity of ultrananocrystalline diamond films by several orders of magnitude. We show that films produced at low... (Read more)
- 530. Phys. Rev. B 74, 235426 (2006) , “First-principles study of electronic properties of hydrogenated graphite”, A. Allouche and Y. FerroProgressive implantation of hydrogen atoms into graphite is modeled by first-principles density functional theory. The maximum H/C ratio was found at 53%, which is in good agreement with experimental results. The hydrogen trapping energy varies from −0.7 eV at very low concentrations to a... (Read more)
- 531. Phys. Rev. B 74, 235317 (2006) , “Impurity conduction in phosphorus-doped buried-channel silicon-on-insulator field-effect transistors at temperatures between 10 and 295 K”, Yukinori Ono, Jean-Francois Morizur, Katsuhiko Nishiguchi, Kei Takashina, Hiroshi Yamaguchi, Kazuma Hiratsuka, Seiji Horiguchi, Hiroshi Inokawa, and Yasuo TakahashiWe investigate transport in phosphorus-doped buried-channel metal-oxide-semiconductor field-effect transistors at temperatures between 10 and 295 K. We focus on transistors with phosphorus donor concentrations higher than those previously studied, where we expect conduction to rely on donor... (Read more)
- 532. Phys. Rev. B 74, 235301 (2006) , “Precursor mechanism for interaction of bulk interstitial atoms with Si(100)”, Xiao Zhang, Min Yu, Charlotte T. M. Kwok, Ramakrishnan Vaidyanathan, Richard D. Braatz, and Edmund G. SeebauerIn the same way that gases react with surfaces from above, solid-state point defects such as interstitial atoms can react from below. Little attention has been paid to this form of surface chemistry. Recent bulk self-diffusion measurements near the Si(100) surface have quantified Si interstitial... (Read more)
- 533. Phys. Rev. B 74, 235214 (2006) , “Raman scattering study of H2 in Si”, M. Hiller, E. V. Lavrov, and J. WeberIsolated interstitial H2 and H2 bound to interstitial oxygen (O–H2) in single-crystalline Si are studied by Raman scattering. Two Raman signals at 3199(1) and 3193(1) cm−1 (T0 K) are identified as ro-vibrational transitions of... (Read more)
- 534. Phys. Rev. B 74, 235213 (2006) , “Mn 3d electronic configurations in (Ga1−xMnx)As ferromagnetic semiconductors and their influence on magnetic ordering”, F. Kronast, R. Ovsyannikov, A. Vollmer, H. A. Dürr, W. Eberhardt, P. Imperia, D. Schmitz, G. M. Schott, C. Ruester, C. Gould, G. Schmidt, K. Brunner, M. Sawicki, and L. W. MolenkampWe applied x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD) at the Mn 2p-3d resonances to study the Mn 3d electronic configuration and the coupling of Mn 3d magnetic moments in various Ga1−xMnxAs films.... (Read more)
- 535. Phys. Rev. B 74, 235210 (2006) , “Dislocation-induced deep electronic states in InP: Photocapacitance measurements”, Yutaka Oyama, Jun-ichi Nishizawa, Toshihiro Kimura, and Takenori TannoPhotocapacitance and excitation photocapacitance methods were applied to reveal the dislocation-induced deep levels in coalescent epitaxial lateral overgrowth layers of InP. Point-contact Schottky barrier junctions with small junction areas were formed on dislocated and dislocation-free regions by... (Read more)
- 536. Phys. Rev. B 74, 235209 (2006) , “Comparison of two methods for circumventing the Coulomb divergence in supercell calculations for charged point defects”, A. F. Wright and N. A. ModineDensity-functional-theory calculations were performed for the unrelaxed +2 Si vacancy and +2 self-interstitial utilizing periodic boundary conditions and two different methods—the uniform background charge method and the local moment counter charge method—for circumventing the divergence... (Read more)
- 537. Phys. Rev. B 74, 235208 (2006) , “Theoretical study of the magnetism of Mn-doped ZnO with and without defects”, D. Iuan, B. Sanyal, and O. ErikssonWe calculate the exchange interaction parameters of a classical Heisenberg Hamiltonian for Mn-doped ZnO (Mn concentration between 5% and 20%) by an ab initio Korringa-Kohn-Rostoker coherent-potential-approximation method in the framework of density functional theory. A weak antiferromagnetic... (Read more)
- 538. Phys. Rev. B 74, 235207 (2006) , “Vacancy-enhanced ferromagnetism in Fe-doped rutile TiO2”, Jun Chen, Paul Rulis, Lizhi Ouyang, S. Satpathy, and W. Y. ChingBased on a series of supercell density functional calculations of Fe-doped TiO2 both with and without O vacancy (VO), we show that VO plays an important role in determining the magnetic properties of the dilute magnetic semiconductors (DMS). Without... (Read more)
- 539. Phys. Rev. B 74, 235205 (2006) , “Optically-detected magnetic resonance of spin-paired complexes emitting in the 2.3 eV spectral region in Mg-doped GaN”, G. N. Aliev, S. Zeng, S. J. Bingham, D. Wolverson, J. J. Davies, T. Wang, and P. J. ParbrookOptically-detected magnetic resonance (ODMR) experiments on magnesium-doped GaN produced by metal-organic vapor phase epitaxy show a group of strong signals with large linewidths (in excess of 0.15 Tesla) obtained when monitoring photoluminescence in the region between 5000 Å and 6200 ... (Read more)
- 540. Phys. Rev. B 74, 235204 (2006) , “Bound excitons in Cu2O: Efficient internal free exciton detector”, J. I. Jang, Y. Sun, B. Watkins, and J. B. KettersonWe report the spectroscopic observation of bound excitons in natural Cu2O samples, which are generated by impurity capture of free excitons. Due to the broken symmetry of a bound exciton, its radiative recombination rate increases, causing a greatly enhanced luminescence intensity... (Read more)
- 541. Phys. Rev. B 74, 235201 (2006) , “Annealing of multivacancy defects in 4H-SiC”, W. E. Carlos, N. Y. Garces, E. R. Glaser, and M. A. FantonThe annealing behavior of defects observed in electron paramagnetic resonance (EPR) and photoluminescence (PL) is discussed. We consider the divacancy (the P6/P7 EPR centers) and a previously unreported EPR center that we suggest is a VC-VSi-VC... (Read more)
- 542. Phys. Rev. B 74, 235104 (2006) , “Longitudinal and transverse diffusion of conduction-electron spins on stacks of fluoranthene radical cations”, David Saez de Jauregui, Jürgen Gmeiner, and Elmar DormannThe temperature dependence and anisotropy of the conduction-electron spin diffusion coefficient D(T) of three single crystals of the organic conductor (fluoranthene)2PF6 with defect content varying between 7×10−5 and 1% per formula unit have... (Read more)
- 543. Phys. Rev. B 74, 233203 (2006) , “Combined photoluminescence-imaging and deep-level transient spectroscopy of recombination processes at stacking faults in 4H-SiC”, A. Galeckas, A. Hallén, S. Majdi, J. Linnros, and P. PirouzWe report on electronic properties of single- and double-layer stacking faults in 4H-SiC and provide an insight into apparent distinctions of recombination-enhanced defect reactions at these faults. Photoluminescence imaging spectroscopy and deep-level transient spectroscopy experiments... (Read more)
- 544. Phys. Rev. B 74, 233201 (2006) , “Electronic and magnetic properties of V-doped anatase TiO2 from first principles”, Xiaosong Du, Qunxiang Li, Haibin Su, and Jinlong YangWe report a first-principles study on the geometric, electronic, and magnetic properties of V-doped anatase TiO2. The DFT+U (Hubbard coefficient) approach predicts semiconductor band structures for Ti1−xVxO2 (x=6.25% and... (Read more)
- 545. Phys. Rev. B 74, 214409 (2006) , “Hyperfine interaction of Er3+ ions in Y2SiO5: An electron paramagnetic resonance spectroscopy study”, O. Guillot-Noël, Ph. Goldner, Y. Le Du, E. Baldit, P. Monnier, and K. BencheikhElectron paramagnetic resonance (EPR) spectroscopy of rare earth ions in crystals is a powerful tool to analyze the hyperfine structure of the rare earth ground state. This can be useful for coherent spectroscopy and quantum information applications where the hyperfine structure of the electronic... (Read more)
- 546. Phys. Rev. B 74, 214109 (2006) , “Inversion of defect interactions due to ordering in Sr1−3x/2LaxTiO3 perovskites: An atomistic simulation study”, B. S. Thomas, N. A. Marks, and Peter HarrowellSr1−3x/2LaxTiO3 perovskites exhibit large variations in radiation resistance and A-site vacancy ordering, depending on x and thermal history. In this study we use a combination of ab initio and classical simulation techniques... (Read more)
- 547. Phys. Rev. B 74, 214105 (2006) , “Atomistic simulations of radiation-induced defect formation in spinels: MgAl2O4, MgGa2O4, and MgIn2O4”, D. Bacorisen, Roger Smith, B. P. Uberuaga, K. E. Sickafus, J. A. Ball, and R. W. GrimesMolecular dynamics simulations of collision cascades were performed in three spinel oxides with varying inversion, namely normal magnesium aluminate, MgAl2O4, half-inverse magnesium gallate, MgGa2O4, and inverse magnesium indate,... (Read more)
- 548. Phys. Rev. B 74, 205428 (2006) , “Er site in Er-implanted Si nanoclusters embedded in SiO2”, C. Maurizio, F. Iacona, F. D'Acapito, G. Franzò, and F. PrioloWe have investigated by extended x-ray absorption fine structure spectroscopy the local order around Er atoms introduced by ion implantation in substoichiometric silica films prepared by plasma enhanced chemical vapor deposition, where Si nanoclusters have been formed by different preimplantation... (Read more)
- 549. Phys. Rev. B 74, 205324 (2006) , “Surface smoothness of plasma-deposited amorphous silicon thin films: Surface diffusion of radical precursors and mechanism of Si incorporation”, Mayur S. Valipa, Tamas Bakos, and Dimitrios MaroudasWe present a detailed analysis of the fundamental atomic-scale processes that determine the surface smoothness of hydrogenated amorphous silicon (a-Si:H) thin films. The analysis is based on a synergistic combination of molecular-dynamics (MD) simulations of radical precursor migration on surfaces... (Read more)
- 550. Phys. Rev. B 74, 205208 (2006) , “Formation energies, binding energies, structure, and electronic transitions of Si divacancies studied by density functional calculations”, R. R. Wixom and A. F. WrightAtomic configurations, formation energies, electronic transition energies, and binding energies of the silicon divacancy in the +1, 0, −1, and −2 charge states were obtained from density functional theory calculations. The calculations were performed using the local density approximation... (Read more)
- 551. Phys. Rev. B 74, 205207 (2006) , “Charge-dependent migration pathways for the Ga vacancy in GaAs”, Fedwa El-Mellouhi, Norm, and MousseauUsing a combination of the local-basis ab initio program SIESTA and the activation-relaxation technique we study the diffusion mechanisms of the gallium vacancy in GaAs. Vacancies are found to diffuse to the second neighbor using two different mechanisms, as well as to the first and fourth... (Read more)
- 552. Phys. Rev. B 74, 205202 (2006) , “Structural model of amorphous silicon annealed with tight binding”, N. Bernstein, J. L. Feldman,, and M. FornariWe present a model of amorphous silicon generated by extensive annealing of a continuous random network structure using a molecular dynamics simulation with forces computed by a tight-binding total energy method. We also produce a refined model by relaxing the annealed model using density functional... (Read more)
- 553. Phys. Rev. B 74, 195207 (2006) , “Magnetic phases and anisotropy in Gd-doped GaN”, L. Pérez, G. S. Lau, S. Dhar, O. Brandt, and K. H. PloogIn this work we present a detailed study of the magnetic properties of GaN:Gd layers with different Gd content (6×1015 to 1×1019 cm−3) grown by reactive molecular beam epitaxy. The temperature dependence of the magnetic properties suggests the... (Read more)
- 554. Phys. Rev. B 74, 195205 (2006) , “Magnetopolaron effect on shallow donors in GaN”, A. Wysmoek, R. Stpniewski, M. Potemski, B. Chwalisz-Pitka, K. Pakua, J. M. Baranowski, D. C. Look, S. S. Park, and K. Y. LeeResonant interaction between longitudinal-optic (LO) phonons and electrons bound on shallow donors in GaN is studied using magnetoluminescence of neutral-donor bound excitons (D0X). The experiments were performed on high-quality freestanding GaN material and heteroepitaxial... (Read more)
- 555. Phys. Rev. B 74, 195204 (2006) , “Interaction of iron with the local environment in SiGe alloys investigated with Laplace transform deep level spectroscopy”, Vl. Kolkovsky, A. Mesli, L. Dobaczewski, N. V. Abrosimov, Z. R. ytkiewicz, and A. R. PeakerLaplace transform deep level transient spectroscopy (LDLTS) is used to investigate the alloy effects on iron related deep centers in Si1−xGex. A clear buildup of alloy disorder as a function of the germanium content has been observed for the isolated... (Read more)
- 556. Phys. Rev. B 74, 195202 (2006) , “Interstitial-mediated mechanisms of As and P diffusion in Si: Gradient-corrected density-functional calculations”, Scott A. Harrison, Thomas F. Edgar, and Gyeong S. HwangGradient-corrected density-functional calculations are used to determine the structure, stability, and diffusion of arsenic-interstitial and phosphorus-interstitial pairs in the positive, neutral, and negative charge states. For both cases, our calculations show that the neutral pair will be... (Read more)
- 557. Phys. Rev. B 74, 195128 (2006) , “First-principles calculations of native defects in tin monoxide”, A. Togo, F. Oba, I. Tanaka, and K. TatsumiThe formation energies and electronic structure of native defects in tin monoxide are investigated by first-principles calculations. Equilibrium defect concentrations, which are obtained using the calculated formation energies and charge neutrality, indicate that the tin vacancy is the dominant... (Read more)
- 558. Phys. Rev. B 74, 195101 (2006) , “Characterization of the hyperfine interaction in europium-doped yttrium orthosilicate and europium chloride hexahydrate”, J. J. Longdell, A. L. Alexander, and M. J. SellarsWe present characterization of the hyperfine interaction for the europium in hydrated europium chloride and as a dopant in yttrium orthosilicate. The Zeeman and pseudoquadrupole tensors were determined by measuring the hyperfine splittings while rotating the direction of a weak (~300 G) magnetic... (Read more)
- 559. Phys. Rev. B 74, 193405 (2006) , “Role of charge in destabilizing AlH4 and BH4 complex anions for hydrogen storage applications: Ab initio density functional calculations”, A. J. Du, Sean C. Smith, and G. Q. LuNaAlH4 and LiBH4 are potential candidate materials for mobile hydrogen storage applications, yet they have the drawback of being highly stable and desorbing hydrogen only at elevated temperatures. In this letter, ab initio density functional theory calculations reveal... (Read more)
- 560. Phys. Rev. B 74, 184117 (2006) , “Ab initio thermodynamic properties of point defects and O-vacancy diffusion in Mg spinels”, Zbigniew odziana and Jacek PiechotaWe report ab initio plane wave density functional theory studies of thermodynamic properties of isolated cation substitutions and oxygen vacancies in magnesium spinel, MgAl2O4. The formation enthalpy of Ca, Cu, and Zn substitutions of Mg cation indicate that transition... (Read more)
- 561. Phys. Rev. B 74, 184108 (2006) , “Interpreting Mössbauer spectra reflecting an infinite number of sites: An application to Fe1−xSi synthesized by pulsed laser annealing”, A. Falepin, S. Cottenier, C. M. Comrie, and A. VantommeWe present a study on the interpretation of conversion electron Mössbauer spectra reflecting an infinite number of sites, in casu Mössbauer spectroscopy on Fe1−xSi layers on Si, synthesized by pulsed laser annealing. These spectra display a broad... (Read more)
- 562. Phys. Rev. B 74, 174407 (2006) , “Superexchange in dilute magnetic dielectrics: Application to (Ti,Co)O2”, K. Kikoin and V. FleurovWe extend the model of ferromagnetic superexchange in dilute magnetic semiconductors to the ferromagnetically ordered highly insulating compounds (dilute magnetic dielectrics). The intrinsic ferromagnetism without free carriers is observed in oxygen-deficient films of anatase TiO2 doped... (Read more)
- 563. Phys. Rev. B 74, 174206 (2006) , “Nuclear quadrupole resonance study of local bonding in glassy AsxSe1−x”, Eungho Ahn, G. A. Williams, and P. C. TaylorNuclear quadrupole resonance (NQR) experiments were performed on glassy AsxSe1−x to study the local structural order. The bonding in AsxSe1−x is governed by preferential bonding (chemical ordering) between arsenic... (Read more)
- 564. Phys. Rev. B 74, 174122 (2006) , “Lithium colloids and color center creation in electron-irradiated Li2NH observed by electron-spin resonance”, F. Beuneu, P. Vajda, Y. Nakamori, and S. OrimoWe have irradiated Li2NH powder with MeV electrons at room temperature and investigated the introduced defects with electron spin resonance. Conduction electron spin resonance indicates the presence of nanosize metallic Li colloids seen as a Lorentzian line with a g=2.0023 and a... (Read more)
- 565. Phys. Rev. B 74, 174120 (2006) , “Single-crystal silicon coimplanted by helium and hydrogen: Evolution of decorated vacancylike defects with thermal treatments”, C. Macchi, S. Mariazzi, G. P. Karwasz, R. S. Brusa, P. Folegati, S. Frabboni, and G. OttavianiSi p-type (100) samples were coimplanted at room temperature with He+ ions at 30 keV with a dose of 1×1016 ions/cm2 and successively with H+ ions at 24 keV with a dose of 1×1016 ions/cm2. A series of samples was... (Read more)
- 566. Phys. Rev. B 74, 174115 (2006) , “Modeling of damage generation mechanisms in silicon at energies below the displacement threshold”, Iván Santos, Luis A. Marqués, and Lourdes PelazWe have used molecular dynamics simulation techniques to study the generation of damage in Si within the low-energy deposition regime. We have demonstrated that energy transfers below the displacement threshold can produce a significant amount of damage, usually neglected in traditional radiation... (Read more)
- 567. Phys. Rev. B 74, 174101 (2006) , “First-principles study of the intrinsic defects in PbFCl”, Bo Liu, Zeming Qi, and Chaoshu ShiFirst-principles pseudopotential calculations have been performed to investigate intrinsic defects including vacancies, interstitials, antisite defects, as well as Schottky and Frenkel defects in PbFCl crystals. For the isolated vacancies and interstitials, their formation energies are critically... (Read more)
- 568. Phys. Rev. B 74, 165404 (2006) , “Density functional study of gold atoms and clusters on a graphite (0001) surface with defects”, Jaakko Akola and Hannu HäkkinenAdsorption of gold atoms and clusters (N=6) on a graphite (0001) surface with defects has been studied using density functional theory. In addition to perfect graphite (0001), three types of surface defects have been considered: a surface vacancy (hole), a pyridinelike defect comprising three... (Read more)
- 569. Phys. Rev. B 74, 165204 (2006) , “Electronic structure of rare-earth impurities in GaAs and GaN”, A. Svane, N. E. Christensen, L. Petit, Z. Szotek, and W. M. TemmermanThe electronic structures of substitutional rare-earth (RE) impurities in GaAs and cubic GaN are calculated. The total energy is evaluated with the self-interaction corrected local spin density approximation, by which several configurations of the open 4f shell of the rare-earth ion are... (Read more)
- 570. Phys. Rev. B 74, 165203 (2006) , “Isotopic-mass dependence of the A, B, and C excitonic band gaps in ZnO at low temperatures”, S. Tsoi, X. Lu, A. K. Ramdas, H. Alawadhi, M. Grimsditch, M. Cardona, and R. LauckLow temperature wavelength-modulated reflectivity measurements of isotopically engineered ZnO samples have yielded the dependence of their A, B, and C excitonic band gaps on the isotopic masses of Zn and O. The observed dependence is analyzed in terms of the band gap renormalization by zero-point... (Read more)
- 571. Phys. Rev. B 74, 165202 (2006) , “Structural and electronic properties of Fe3+ and Fe2+ centers in GaN from optical and EPR experiments”, E. Malguth, A. Hoffmann, W. Gehlhoff, O. Gelhausen, M. R. Phillips, and X. XuThis work provides a consistent picture of the structural, optical, and electronic properties of Fe-doped GaN. A set of high-quality GaN crystals doped with Fe at concentrations ranging from 5×1017 cm3 to 2×1020 cm3 is... (Read more)
- 572. Phys. Rev. B 74, 165201 (2006) , “Internal 5E ? 5T2 transition of Fe2+ in GaN”, E. Malguth, A. Hoffmann, and X. XuWe present Fourier transform infrared transmission measurements on Fe-doped GaN. A set of freestanding high-quality GaN:Fe samples with varying Fe concentrations shows a rich absorption structure around 390 meV which is unambiguously assigned to the internal... (Read more)
- 573. Phys. Rev. B 74, 165116 (2006) , “Density-functional-theory calculations for the silicon vacancy”, A. F. WrightThe atomic configurations and formation energies of a silicon vacancy in the +2, +1, 0, −1, and −2 charge states have been computed using density-functional theory with norm-conserving pseudopotentials and a plane wave basis. Calculations were performed in simple cubic supercells using... (Read more)
- 574. Phys. Rev. B 74, 161203(R) (2006) , “Room-temperature manipulation and decoherence of a single spin in diamond”, R. Hanson, O. Gywat, and D. D. AwschalomWe report on room-temperature coherent manipulation of the spin of a single nitrogen-vacancy center in diamond and a study of its coherence as a function of magnetic field. We use magnetic resonance to induce Rabi nutations and apply a Hahn spin echo to remove the effect of low-frequency dephasing.... (Read more)
- 575. Phys. Rev. B 74, 161202 (2006) , “Deactivation of Li by vacancy clusters in ion-implanted and flash-annealed ZnO”, T. Moe Børseth, F. Tuomisto, J. S. Christensen, W. Skorupa, E. V. Monakhov, B. G. Svensson, and A. Yu. KuznetsovLi is present in hydrothermally grown ZnO at high concentrations and is known to compensate both n- and p-type doping due to its amphoteric nature. However, Li can be manipulated by annealing and ion implantation in ZnO. Fast, 20 ms flash anneals in the 9001400 °C range... (Read more)
- 576. Phys. Rev. B 74, 161201 (2006) , “Detection of magnetic resonance of donor-bound electrons in GaAs by Kerr rotation”, T. A. Kennedy, J. Whitaker, A. Shabaev, A. S. Bracker, and D. GammonMagnetic resonance of electrons in lightly doped GaAs layers has been detected at 5.8 T by magneto-optical Kerr rotation. A study over a wide range of microwave powers shows (1) resonance without dynamic nuclear polarization (DNP), (2) resonance enhanced by DNP, and (3) DNP pinning of the resonance... (Read more)
- 577. Phys. Rev. B 74, 155429 (2006) , “Effect of nitrogen on the electronic properties of ultrananocrystalline diamond thin films grown on quartz and diamond substrates”, P. Achatz, O. A. Williams, P. Bruno, D. M. Gruen, J. A. Garrido, and M. StutzmannThe electronic transport properties of ultrananocrystalline diamond thin films grown from an argon-rich Ar/CH4 microwave plasma have been investigated in the temperature range from 300 up to 700 K and as a function of nitrogen added to the gas phase (from 0 to 20%). The influence of... (Read more)
- 578. Phys. Rev. B 74, 155425 (2006) , “Ab initio study of native defects in SiC nanotubes”, R. J. Baierle, P. Piquini, L. P. Neves, and R. H. MiwaSpin-polarized density functional theory is used to investigate the electronic and structural properties of vacancies and antisites in zigzag, armchair, and chiral SiC nanotubes. Antisites present lower formation energies compared to vacancies, introducing an empty electronic level close to the... (Read more)
- 579. Phys. Rev. B 74, 155310 (2006) , “Optical study of excitation and deexcitation of Tm in GaN quantum dots”, Thomas Andreev, Nguyen Quang Liem, Yuji Hori, Mitsuhiro Tanaka, Osamu Oda, Daniel Le Si Dang, Bruno Daudin, and Bruno GayralWe report on the optical properties of molecular beam epitaxy grown GaN quantum dots (QDs) doped with Tm. Under optical excitation above the fundamental energy of GaN QDs, the fundamental transition emission from the GaN QD host was not observed while bright emission from Tm3+ manifolds... (Read more)
- 580. Phys. Rev. B 74, 155208 (2006) , “Vibrational spectra of vitreous germania from first-principles”, Luigi Giacomazzi, P. Umari, and Alfredo PasquarelloWe report on a first-principles investigation of the structural and vibrational properties of vitreous germania (v-GeO2). Our work focuses on a periodic model structure of 168 atoms, but three smaller models are also studied for comparison. We first carry out a detailed structural... (Read more)
- 581. Phys. Rev. B 74, 155205 (2006) , “Ab initio studies of the electronic structure of defects in PbTe”, Salameh Ahmad, S. D. Mahanti, Khang Hoang, and M. G. KanatzidisUnderstanding the detailed electronic structure of deep defect states in narrow band-gap semiconductors has been a challenging problem. Recently, self-consistent ab initio calculations within density functional theory using supercell models have been successful in tackling this problem. In... (Read more)
- 582. Phys. Rev. B 74, 155204 (2006) , “Vibronic spectrum of c-BN measured with cathodoluminescence”, C. Manfredotti, R. Cossio, A. Lo Giudice, E. Vittone, and F. FizzottiAn extended vibronic spectrum (up to six phonon replicas) has been measured by low temperature cathodoluminescence in pure c-BN microcrystalline samples obtained by high temperature high pressure method. The zero phonon line, found at 3.573 eV, should be connected to a center identified... (Read more)
- 583. Phys. Rev. B 74, 155203 (2006) , “Antisite effect on hole-mediated ferromagnetism in (Ga,Mn)As”, R. C. Myers, B. L. Sheu, A. W. Jackson, A. C. Gossard, P. Schiffer, N. Samarth, and D. D. AwschalomWe study the Curie temperature and hole density of (Ga,Mn)As while systematically varying the As-antisite density. Hole compensation by As-antisites limits the Curie temperature and can completely quench long-range ferromagnetic order in the low doping regime of 1%2% Mn. Samples are grown by... (Read more)
- 584. Phys. Rev. B 74, 155201 (2006) , “Crystal-field theory of Co2+ in doped ZnO”, R. O. Kuzian, A. M. Daré, P. Sati, and R. HaynWe present a crystal-field theory of transition-metal impurities in semiconductors in a trigonally distorted tetrahedral coordination. We develop a perturbative scheme to treat covalency effects within the weak ligand field case (Coulomb interaction dominates over one-particle splitting) and apply... (Read more)
- 585. Phys. Rev. B 74, 153403 (2006) , “Doping and the unique role of vacancies in promoting the magnetic ground state in carbon nanotubes and C60 polymers”, Antonis N. Andriotis, R. Michael Sheetz, and Madhu MenonThe role of various types of defects in establishing the magnetic properties of the C60-based polymers and the single-wall carbon nanotubes is investigated. Comparing the role of carbon vacancies, and that of substitutional impurity atoms X (X=N, B, O, Si, P, and S) in... (Read more)
- 586. Phys. Rev. B 74, 153311 (2006) , “Electron transport in laterally confined phosphorus δ layers in silicon”, S. J. Robinson, J. S. Kline, H. J. Wheelwright, J. R. Tucker, C. L. Yang, R. R. Du, B. E. Volland, I. W. Rangelow, and T.-C. ShenTwo-dimensional electron systems fabricated from a single layer of P-donors have been lithographically confined to nanometer scale in lateral directions. The electronic transport of such quasi-one-dimensional systems with and without a perpendicular magnetic field was characterized at cryogenic... (Read more)
- 587. Phys. Rev. B 74, 153201 (2006) , “Light-induced hyperfine 69Ga shifts in semi-insulating GaAs observed by optically polarized NMR”, Kannan Ramaswamy, Stacy Mui, and Sophia E. HayesWe report the observation of 69Ga NMR light induced hyperfine shifts at 6 K in semi-insulating GaAs detected by optically polarized nuclear magnetic resonance in a magnetic field of 4.7 T. The main features of the observed shift are a systematic change in the absolute shift value as the... (Read more)
- 588. Phys. Rev. B 74, 144432 (2006) , “Role of defects in ferromagnetism in Zn1−xCoxO: A hybrid density-functional study”, C. H. PattersonExperimental studies of Zn1−xCoxO as thin films or nanocrystals have found ferromagnetism and Curie temperatures above room temperature and that p- or n-type doping of Zn1−xCoxO can change its magnetic... (Read more)
- 589. Phys. Rev. B 74, 144106 (2006) , “Density functional theory calculation of the DI optical center in SiC”, T. A. G. Eberlein, R. Jones, S. Öberg, and P. R. BriddonThe DI center is a prominent defect which is detected in as-grown or irradiated SiC. It is unusual in that its intensity grows with heat treatments and survives anneals of 1700 °C. It has been assigned recently to either a close-by antisite pair or to the close-by antisite... (Read more)
- 590. Phys. Rev. B 74, 140502(R) (2006) , “Lattice parameters and thermal expansion of superconducting boron-doped diamonds”, V. V. Brazhkin, E. A. Ekimov, A. G. Lyapin, S. V. Popova, A. V. Rakhmanina, S. M. Stishov, V. M. Lebedev, Y. Katayama, and K. KatoUsing two different high-pressure techniques, we have prepared boron-doped diamonds with atomic concentration of the dopant ranging from 0.04% to 4% (from 7×1019 to 7×1021 atom/cm3) and studied the lattice constants and thermal expansion of the diamonds... (Read more)
- 591. Phys. Rev. B 74, 134418 (2006) , “Electron spin resonance and its implication on the maximum nuclear polarization of deuterated solid target materials”, J. Heckmann, W. Meyer, E. Radtke, G. Reicherz, and S. GoertzESR spectroscopy is an important tool in polarized solid target material research, since it allows us to study the paramagnetic centers, which are used for the dynamic nuclear polarization (DNP). The polarization behavior of the different target materials is strongly affected by the properties of... (Read more)
- 592. Phys. Rev. B 74, 134303 (2006) , “1H NMR study of proton dynamics in Cs5H3(SO4)4·xH2O”, Koh-ichi Suzuki and Shigenobu HayashiComplicated phase relations in Cs5H3(SO4)4·xH2O are revealed by thermal analyses. A superprotonic phase transition takes place at 420 K for both the hydrated and the anhydrous forms. The 1H magic-angle-spinning (MAS) NMR... (Read more)
- 593. Phys. Rev. B 74, 134102 (2006) , “Phosphorous–oxygen hole centers in phosphosilicate glass films”, M. Fanciulli, E. Bonera, S. Nokhrin, and G. PacchioniPhosphosilicate glass films produced by subatmospheric pressure chemical vapor deposition with different phosphorus concentrations have been investigated by ultraviolet Raman spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. The behavior and the attribution of the main Raman band... (Read more)
- 594. Phys. Rev. B 74, 132107 (2006) , “Evidence of extended defects in pure zirconia irradiated by swift heavy ions”, Gianguido Baldinozzi, David Simeone, Dominique Gosset, Isabelle Monnet, Sophie Le Caër, and Léo MazerollesX-ray diffraction, transmission electron microscopy, and optical spectroscopy were used to investigate the microstructure of polycrystalline samples of pure monoclinic zirconia irradiated by high energy ions. These techniques point out the existence of extended defects and they allow to monitor the... (Read more)
- 595. Phys. Rev. B 74, 125203 (2006) , “Density functional theory of structural transformations of oxygen-deficient centers in amorphous silica during hole trapping: Structure and formation mechanism of the Egamma[prime]" align="middle"> center”, T. Uchino and T. YokoWe investigate the hole trapping process of a neutral oxygen vacancy in amorphous silicon dioxide (a-SiO2) using cluster calculations based on the density functional theory (DFT) method. We show that trapping a hole at a neutral oxygen vacancy leads to the formation of several... (Read more)
- 596. Phys. Rev. B 74, 121201 (2006) , “Prediction of the anomalous fluorine-silicon interstitial pair diffusion in crystalline silicon”, Scott A. Harrison, Thomas F. Edgar, and Gyeong S. HwangWe propose a diffusion pathway for a fluorine-silicon interstitial pair (F-Sii) in silicon based on extensive first-principles density functional calculations. We find the F-Sii pair to be most stable in the singly positive charge state under intrinsic conditions and can exist... (Read more)
- 597. Phys. Rev. B 74, 115203 (2006) , “From ferromagnetic to antiferromagnetic interactions in n-type Zn1–xMnxO: An electron paramagnetic resonance study”, A. Ben Mahmoud, H. J. von Bardeleben, J. L. Cantin, A. Mauger, E. Chikoidze, and Y. DumontContradictory results concerning the formation of a ferromagnetic state in Mn doped ZnO layers have been reported in the last years. We present the results of an electron paramagnetic resonance study on homogeneous single phase n-type conductive Zn1xMnxO... (Read more)
- 598. Phys. Rev. B 74, 115201 (2006) , “Magnetic circular dichroism spectra in a II-VI diluted magnetic semiconductor Zn1–xCrxTe: First-principles calculations”, Hongming Weng, Jinming Dong, Tomoteru Fukumura, Masashi Kawasaki, and Yoshiyuki KawazoeThe absorption and magnetic circular dichroism (MCD) spectra of Zn1xCrxTe for x=0.0625, 0.25, and 1.0 are studied using the first-principles method. The calculated MCD spectra are found to be well consistent with the experimental measurement at the... (Read more)
- 599. Phys. Rev. B 74, 115118 (2006) , “Optical properties of Cr3+ –doped oxides: Different behavior of two centers in alexandrite”, J. M. García-Lastra, J. A. Aramburu, M. T. Barriuso, and M. MorenoThis work is aimed at explaining the different color exhibited by the two Cr3+ centers in the alexandrite gemstone as well as ruby and emerald. Although the average Cr3+-O2 distance in ruby, emerald, and the Cs center in alexandrite is known... (Read more)
- 600. Phys. Rev. B 74, 113301 (2006) , “Reactions of excess hydrogen at a Si(111) surface with H termination: First-principles calculations”, L. Tsetseris, S. T. PantelidesHydrogen reactions with silicon substrates is an established technique for the study and control of surface morphology. Here, we report the results of first-principles calculations on the trapping and depassivation reactions involving excess hydrogen (x-H) at a fully H-passivated Si(111) surface. We find that x-H atoms can depassivate Si-H bonds with a small barrier of 0.8 eV, or they can get trapped in very stable configurations that comprise of a dihydride and a vicinal Si-H bond. Desorption of H2 molecules from these complexes has an activation energy of 1.68 eV, which can account for pertinent experimental data. We discuss also the effect of strain on the possibility of altering the x-H surface profile. (Read more)
- 601. Phys. Rev. B 74, 104303 (2006) , “Nitrogen-vacancy center in diamond: Model of the electronic structure and associated dynamics”, N. B. Manson, J. P. Harrison, and M. J. SellarsSymmetry considerations are used in presenting a model of the electronic structure and the associated dynamics of the nitrogen-vacancy center in diamond. The model accounts for the occurrence of optically induced spin polarization, for the change of emission level with spin polarization and for new... (Read more)
- 602. Phys. Rev. B 74, 100201(R) (2006) , “Direct spectroscopic observation of the atomic-scale mechanisms of clustering and homogenization of rare-earth dopant ions in vitreous silica”, Sabyasachi Sen, Rafail Rakhmatullin, Ruslan Gubaidullin, and Andreas PöpplStructural aspects of clustering of rare earth ions in oxide glasses have been studied for the last several years in relation to their applications in photonics. However, the mechanism of homogenization of the spatial distribution of rare earth ions by codoping, typically with Al or P, is still not... (Read more)
- 603. Phys. Rev. B 74, 085201 (2006) , “Hydrogen dynamics and light-induced structural changes in hydrogenated amorphous silicon”, T. A. Abtew and D. A. DraboldWe use accurate first-principles methods to study the network dynamics of hydrogenated amorphous silicon, including the motion of hydrogen. In addition to studies of atomic dynamics in the electronic ground state, we also adopt a simple procedure to track the H dynamics in light-excited states.... (Read more)
- 604. Phys. Rev. B 74, 081201 (2006) , “Design of shallow acceptors in ZnO: First-principles band-structure calculations”, Jingbo Li, Su-Huai Wei, Shu-Shen Li, and Jian-Bai Xiap-type doping is a great challenge for the full utilization of ZnO as short-wavelength optoelectronic material. Due to a large electronegative characteristic of oxygen, the ionization energy of acceptors in ZnO is usually too high. By analyzing the defect wave-function character, we propose... (Read more)
- 605. Phys. Rev. B 74, 075332 (2006) , “Point defects on the (110) surfaces of InP, InAs, and InSb: A comparison with bulk”, A. Höglund, C. W. M. Castleton, M. Göthelid, B. Johansson,, and S. MirbtThe basic properties of point defects, such as local geometries, positions of charge-transfer levels, and formation energies, have been calculated using density-functional theory, both in the bulk and on the (110) surface of InP, InAs, and InSb. Based on these results we discuss the electronic... (Read more)
- 606. Phys. Rev. B 74, 064116 (2006) , “Charge centers in CaF2: Ab initio calculation of elementary physical properties”, M. Letz and L. ParthierCharge centers in ionic crystals provide a channel for elementary interaction between electromagnetic radiation and the lattice. We calculate the electronic ground-state energies which are needed to create a charge centernamely an F center and an H center. In good agreement with... (Read more)
- 607. Phys. Rev. B 74, 064105 (2006) , “Defect formation in LaGa(Mg,Ni)O3–δ: A statistical thermodynamic analysis validated by mixed conductivity and magnetic susceptibility measurements”, E. N. Naumovich, V. V. Kharton, A. A. Yaremchenko, M. V. Patrakeev, D. G. Kellerman, D. I. Logvinovich, and V. L. KozhevnikovA statistical thermodynamic approach to analyze defect thermodynamics in strongly nonideal solid solutions was proposed and validated by a case study focused on the oxygen intercalation processes in mixed-conducting LaGa0.65Mg0.15Ni0.20O3δ... (Read more)
- 608. Phys. Rev. B 74, 054111 (2006) , “EPR investigation of iron-related centers in 57Fe-doped KTaO3”, P. G. Baranov, A. G. Badalyan, D. V. Azamat, V. A. Trepakov, A. P. Bundakova, E. A. Ruzanova, V. S. Vikhnin, H. Hesse, and S. E. KapphanThree dominant iron centers are studied in the as-grown 57Fe-doped single KTaO3 crystals. For each of the centers, which were labeled as rhombic FeTa3+ and two axial Fe-related centers FeK3+-OI and (Fe). The... (Read more)
- 609. Phys. Rev. B 74, 045217 (2006) , “Vacancy clustering and diffusion in silicon: Kinetic lattice Monte Carlo simulations”, Benjamin P. Haley, Keith M. Beardmore, and Niels Grønbech-JensenDiffusion and clustering of lattice vacancies in silicon as a function of temperature, concentration, and interaction range are investigated by kinetic lattice Monte Carlo simulations. It is found that higher temperatures lead to larger clusters with shorter lifetimes on average, which grow by... (Read more)
- 610. Phys. Rev. B 74, 045213 (2006) , “Hyperfine interaction and magnetoresistance in organic semiconductors”, Y. Sheng, T. D. Nguyen, G. Veeraraghavan, Ö. Mermer, M. Wohlgenannt, S. Qiu, and U. ScherfWe explore the possibility that hyperfine interaction causes the recently discovered organic magnetoresistance (OMAR) effect. We deduce a simple fitting formula from the hyperfine Hamiltonian that relates the saturation field of the OMAR traces to the hyperfine coupling constant. We compare the... (Read more)
- 611. Phys. Rev. B 74, 045211 (2006) , “Auger recombination and biexcitons in Cu2O: A case for dark excitonic matter”, J. I. Jang and J. P. WolfeThe lifetime of excitons in Cu2O decreases significantly at high gas densities. This effect has been attributed to an Auger recombination process between two excitons, resulting in a loss rate given by 1=An, where A is the Auger constant and n... (Read more)
- 612. Phys. Rev. B 74, 045208 (2006) , “Defects in virgin and N+-implanted ZnO single crystals studied by positron annihilation, Hall effect, and deep-level transient spectroscopy”, G. Brauer, W. Anwand, W. Skorupa, J. Kuriplach, O. Melikhova, C. Moisson, H. von Wenckstern, H. Schmidt, M. Lorenz, and M. GrundmannHigh-quality single crystals of ZnO in the as-grown and N+ ion-implanted states have been investigated using a combination of three experimental techniquesnamely, positron lifetime/slow positron implantation spectroscopy accompanied by theoretical calculations of the positron... (Read more)
- 613. Phys. Rev. B 74, 045204 (2006) , “Donor-acceptor pairs in the confined structure of ZnO nanocrystals”, Serguei B. Orlinskii, Hubert Blok, and Jan SchmidtThe electron paramagnetic resonance signal of an exchange-coupled pair consisting of a shallow interstitial Li donor and a deep Na-related acceptor has been identified in ZnO nanocrystals with radii smaller than 1.5 nm. From electron nuclear double resonance experiments it is concluded that the... (Read more)
- 614. Phys. Rev. B 74, 045202 (2006) , “Effects of cation d states on the structural and electronic properties of III-nitride and II-oxide wide-band-gap semiconductors”, Anderson Janotti, David Segev, and Chris G. Van de WalleUsing first-principles methods based on density functional theory within the local density approximation (LDA) we calculate the structural and electronic properties of wurtzite MgO, ZnO, and CdO, and discuss their similarities and dissimilarities with the corresponding Group-III nitrides AlN, GaN,... (Read more)
- 615. Phys. Rev. B 74, 035309 (2006) , “Structure of the interface between ultrathin SiO2 films and 4H-SiC(0001)”, Mark Schürmann, Stefan Dreiner, Ulf Berges, and Carsten WestphalThe interface between ultrathin SiO2 films and 4H-SiC(0001) has been studied by x-ray photoelectron spectroscopy (XPS) and photoelectron diffraction. The investigation was performed for two different films. An ordered silicate layer showed a clear (×)R30°... (Read more)
- 616. Phys. Rev. B 74, 035213 (2006) , “Bound exciton states of isoelectronic centers in GaAs:N grown by an atomically controlled doping technique”, Takashi Kita and Osamu WadaWe have studied bound exciton states of isoelectronic centers of nitrogen-doped GaAs by photoluminescence (PL) spectroscopy. The nitrogen doping has been performed in an atomically controlled way using the (3×3) nitrogen stable surface on GaAs(001), which has succeeded in forming a series of... (Read more)
- 617. Phys. Rev. B 74, 035210 (2006) , “Density-functional electronic structure calculations for native defects and Cu impurities in CdS”, Kazume Nishidate, Takuya Sato, Yuta Matsukura, Mamoru Baba, and Masayuki HasegawaWe performed density-functional electronic structure calculations for wurtzite CdS with native defects and Cu impurity. We investigate formation energies and ionization levels of the defects in various charge states. Our results reveal that the S vacancy is a double donor with the strongly localized... (Read more)
- 618. Phys. Rev. B 74, 035208 (2006) , “Ultranarrow photoluminescence transitions of nitrogen cluster bound excitons in dilute GaAsN”, D. Karaiskaj, A. Mascarenhas, M. Adamcyk, E. C. Young, and T. TiedjeHigh resolution photoluminescence spectroscopy on heavily doped GaAs:N reveals the existence of excitons bound to a nitrogen cluster. The observed transitions are exceedingly sharp, similar to those observed for excitons bound to nitrogen pairs in high quality GaAs with the narrowest transition... (Read more)
- 619. Phys. Rev. B 74, 035205 (2006) , “Mechanisms of arsenic clustering in silicon”, F. F. Komarov, O. I. Velichko, V. A. Dobrushkin, and A. M. MironovA model of arsenic clustering in silicon is proposed and analyzed. The main feature of the proposed model is the assumption that negatively charged arsenic complexes play a dominant role in the clustering process. To confirm this assumption, electron density and concentration of impurity atoms... (Read more)
- 620. Phys. Rev. B 74, 035202 (2006) , “Computation of the Stark effect in P impurity states in silicon”, A. Debernardi, A. Baldereschi, and M. FanciulliWe compute within the effective-mass theory and without adjustable parameters the Stark effect for shallow P donors in Si with anisotropic band structure. Valley-orbit coupling is taken into account in a nonperturbative way and scattering effects of the impurity core are included to properly... (Read more)
- 621. Phys. Rev. B 74, 035112 (2006) , “Charge localization or itineracy at LaAlO3/SrTiO3 interfaces: Hole polarons, oxygen vacancies, and mobile electrons”, R. Pentcheva and W. E. PickettWhile correlated electron behavior is to be expected at oxide interfaces (IFs) involving Mott insulators, we show how strong correlations in the oxygen 2p states may be necessary to account for observed insulating behavior at charged (001)-IFs between the band insulators LaAlO3 and... (Read more)
- 622. Phys. Rev. B 74, 033309 (2006) , “Effect of the triplet state on the random telegraph signal in Si n-MOSFETs”, Enrico Prati, Marco Fanciulli, Giorgio Ferrari, and Marco SampietroWe report on the static magnetic field dependence of the random telegraph signal in a submicrometer silicon n-metal-oxide-semiconductor field-effect transistor. Using intense magnetic fields and low temperatures, we find that the characteristic time ratio changes by three orders of magnitude... (Read more)
- 623. Phys. Rev. B 74, 033304 (2006) , “5-7-5 line defects on As/Si(100): A general stress-relief mechanism for V/IV surfaces”, W. E. McMahon, Iskander G. Batyrev, T. Hannappel, J. M. Olson, and S. B. ZhangAn entire family of nano-scale trenches, ridges, and steps has been observed experimentally on AsH3-exposed Si(100). Some of these line structures have been observed previously, but their structures have remained a mystery. Theoretical modeling shows that they are all based upon the same... (Read more)
- 624. Phys. Rev. B 74, 024106 (2006) , “Oxygen-vacancy-related dielectric anomaly in CaCu3Ti4O12: Post-sintering annealing studies”, C. C. Wang and L. W. ZhangThe influence of post-sintering annealing on the dielectric properties of CaCu3Ti4O12 was investigated in the temperature range form 200 to 400 K. A dielectric peak featuring thermally activated Debye-like behavior was observed around 340 K (100 Hz). This peak... (Read more)
- 625. Phys. Rev. B 73, 33201 (2006) , “Manganese on various lattice sites in (Ga,Mn)As investigated using electron paramagnetic resonance”, T. WeiersThe differences between variously doped and grown samples of manganese-doped GaAs have been studied and set in relation to the magnetic and electronic properties of these materials. For interion exchange and contrary to the resolved hyperfine and crystal field contributions from the ionized acceptor... (Read more)
- 626. Phys. Rev. B 73, 245415 (2006) , “Ab initio study of nitrogen and boron substitutional impurities in single-wall SiC nanotubes”, A. GaliSilicon carbide nanotubes have a great potential for application in chemical sensors in harsh environment or in biological sensors. It is of interest to explore the electronic properties of these nanotubes, and how those are modified in the presence of impurities. It is well known that nitrogen and... (Read more)
- 627. Phys. Rev. B 73, 245211 (2006) , “Hydrogen and muonium in diamond: A path-integral molecular dynamics simulation”, Carlos P. Herrero, Rafael Ramírez, and Eduardo R. HernándezIsolated hydrogen, deuterium, and muonium in diamond have been studied by path-integral molecular dynamics simulations in the canonical ensemble. Finite-temperature properties of these point defects were analyzed in the range from 100 to 800 K. Interatomic interactions were modeled by a... (Read more)
- 628. Phys. Rev. B 73, 245210 (2006) , “First-principles investigation of a bistable boron-oxygen interstitial pair in Si”, A. Carvalho, R. Jones, M. Sanati, S. K. Estreicher, J. Coutinho, and P. R. BriddonLocal density functional calculations are used to predict and compare the properties of the two distinct interstitial boron-interstitial oxygen (BiOi) complexes recently reported in the literature. The electronic and free energies, as well as the small... (Read more)
- 629. Phys. Rev. B 73, 245207 (2006) , “Photoionization measurement of deep defects in single-crystalline CVD diamond using the transient-current technique”, J. Isberg, A. Tajani, and D. J. TwitchenWe have adopted the transient-current technique as a sensitive method to detect small concentrations of charged defects in diamond and to study its photoionization spectrum. It is found that ionized impurity concentrations in the interval 1091013 cm3 can... (Read more)
- 630. Phys. Rev. B 73, 245203 (2006) , “Diffusion mechanisms for silicon di-interstitials”, Yaojun A. Du, Richard G. Hennig, and John W. WilkinsTight-binding molecular dynamics and density-functional simulations on silicon seeded with a di-interstitial reveal its detailed diffusion mechanisms. The lowest-energy di-interstitial performs a translation/rotation diffusion-step with a barrier of 0.3 eV and a prefactor of 11 THz followed by a... (Read more)
- 631. Phys. Rev. B 73, 235213 (2006) , “Donor-vacancy complexes in Ge: Cluster and supercell calculations”, J. Coutinho, S. Öberg, V. J. B. Torres, M. Barroso, R. Jones, and P. R. BriddonWe present a comprehensive spin-density functional modeling study of the structural and electronic properties of donor-vacancy complexes (PV, AsV, SbV, and BiV) in Ge crystals. Special attention is paid to spurious results which are related to the choice of the boundary... (Read more)
- 632. Phys. Rev. B 73, 235211 (2006) , “Ab initio calculations for the interconversion of optically active defects in amorphous silica”, M. M. G. Alemany and James R. ChelikowskyUsing ab initio calculations on clusters, we have identified a new reaction path between the dicoordinated silicon atom defect and the paramagnetic Egamma[prime]" align="middle"> center in amorphous silica. Under ionizing irradiation, the dicoordinated silicon atom... (Read more)
- 633. Phys. Rev. B 73, 235209 (2006) , “Temperature dependence of the vibrational spectrum of a Li-OH complex in ZnO: Infrared absorption experiments and theory”, Kevin R. Martin, Philip Blaney, Gang Shi, Michael Stavola, and W. Beall FowlerConsiderable interest has developed in the potential use of IIVI oxides as electronic and optical materials. In several cases, alkali atoms have been suggested as dopants. We report on the theoretical and experimental investigation of infrared and vibrational properties of a Li-OH complex in... (Read more)
- 634. Phys. Rev. B 73, 235206 (2006) , “LSDA+U study of cupric oxide: Electronic structure and native point defects”, Dangxin Wu and Qiming ZhangA first-principles study on strongly correlated monoclinic cupric oxide CuO has been performed by using the LSDA+U method. The optimized structural parameters of the crystal CuO are in good agreement with the experimental data. The electronic structures and magnetic properties calculated from the... (Read more)
- 635. Phys. Rev. B 73, 233204 (2006) , “Point defects in Ce-doped Y3Al5O12 crystal scintillators”, C. L. Wang, D. Solodovnikov, and K. G. LynnDefect properties of Ce-doped and undoped Y3Al5O12 (YAG) crystals were studied by Doppler broadening of positron annihilation rays and thermoluminescence (TL) as a function of temperature (25300 °C). The positron diffusion length L+ was... (Read more)
- 636. Phys. Rev. B 73, 214113 (2006) , “Point-defect recombination efficiency at grain boundaries in irradiated SiC”, Andrea Moriani and Fabrizio CleriWe studied the atomic-scale mechanisms of radiation damage recovery, by molecular dynamics simulations of irradiation cascades in a -SiC model system, containing one general (001) twist grain boundary in the direction approximately perpendicular to the cascade. The (001) grain boundary has a... (Read more)
- 637. Phys. Rev. B 73, 205205 (2006) , “Photoluminescence from the nitrogen-perturbed above-bandgap states in dilute GaAs1–xNx alloys: A microphotoluminescence study”, P. H. Tan, X. D. Luo, Z. Y. Xu, Y. Zhang, A. Mascarenhas, H. P. Xin, C. W. Tu, and W. K. GeUsing microphotoluminescence (µ-PL), in dilute N GaAs1xNx alloys, we observe a PL band far above the bandgap E0 with its peak energy following the so-called E+ transition, but with contribution from perturbed... (Read more)
- 638. Phys. Rev. B 73, 205203 (2006) , “First-principles study of intrinsic point defects in ZnO: Role of band structure, volume relaxation, and finite-size effects”, Paul Erhart, Karsten Albe, and Andreas KleinDensity-functional theory (DFT) calculations of intrinsic point defect properties in zinc oxide were performed in order to remedy the influence of finite-size effects and the improper description of the band structure. The generalized gradient approximation (GGA) with empirical self-interaction... (Read more)
- 639. Phys. Rev. B 73, 195209 (2006) , “Electrical activity of the PtH2 complex in silicon: High-resolution Laplace deep-level transient spectroscopy and uniaxial-stress technique”, Vl. Kolkovsky, O. Andersen, L. Dobaczewski, A. R. Peaker, and K. Bonde NielsenHigh-resolution Laplace deep-level spectroscopy combined with the uniaxial stress technique has been used to study stress-energy piezospectroscopic tensor components of the platinum-dihydrogen complex in silicon. The effect of stress on the defect has been observed either as the stress-induced... (Read more)
- 640. Phys. Rev. B 73, 195206 (2006) , “Relaxations and bonding mechanism in Hg1–xCdxTe with mercury vacancy defect: First-principles study”, L. Z. Sun, Xiaoshuang Chen, Y. L. Sun, X. H. Zhou, Zh. J. Quan, He Duan, and Wei LuThe structural and electronic properties of the mercury vacancy defect in Hg1xCdxTe have been studied by combining the full-potential linear augmented plane wave and plane-wave pseudopotential method base on the density functional theory. Structural... (Read more)
- 641. Phys. Rev. B 73, 195204 (2006) , “Hydrogen migration in single crystal and polycrystalline zinc oxide”, N. H. NickelHydrogen diffusion in single crystal and polycrystalline zinc oxide was investigated by deuterium diffusion and hydrogen effusion experiments. Deuterium concentration depth profiles were measured as a function of the passivation temperature, while in H effusion experiments the molecular hydrogen... (Read more)
- 642. Phys. Rev. B 73, 193203 (2006) , “Theoretical study of the phosphorus vacancy in ZnGeP2”, Xiaoshu Jiang, M. S. Miao, and Walter R. L. LambrechtFirst-principles calculations are presented for the phosphorus vacancy VP in ZnGeP2, using full-potential linearized muffin-tin orbital supercell local density functional theory calculations. We find the VP to have a high energy of formation compared to... (Read more)
- 643. Phys. Rev. B 73, 193202 (2006) , “First-principles study of point defects in rutile TiO2–x”, Eunae Cho, Seungwu Han, Hyo-Shin Ahn, Kwang-Ryeol Lee, Seong Keun Kim, and Cheol Seong HwangWe report our first-principles results on point defects in TiO2 in the rutile phase. Both the oxygen vacancy and titanium interstitial are considered. The size effect of the supercell has been examined and the localized state associated with the oxygen vacancy turns out to be sensitive to... (Read more)
- 644. Phys. Rev. B 73, 184122 (2006) , “Off-center instability in SrCl2:Fe+: Role of unoccupied 4p orbitals”, P. García-Fernández, J. A. Aramburu, M. T. Barriuso, and M. MorenoRecent electron nuclear double resonance experiments on the Fe(II) center in SrCl2:Fe+ have unambiguously demonstrated that an isolated Fe+ impurity (without any close defect) undergoes a big off-center motion along 001 type directions. As Fe+ in... (Read more)
- 645. Phys. Rev. B 73, 184105 (2006) , “Iron-oxygen vacancy defect association in polycrystalline iron-modified PbZrO3 antiferroelectrics: Multifrequency electron paramagnetic resonance and Newman superposition model analysis”, Hrvoje Metri, Rüdiger-A. Eichel, Klaus-Peter Dinse, Andrew Ozarowski, Johan van Tol, Louis Claude Brunel, Hans Kungl, Michael J. Hoffmann, Kristin A. Schönau, Michael Knapp, and Hartmut FuessBy utilizing multifrequency electron paramagnetic resonance (EPR) spectroscopy, the iron functional center in Fe3+-modified polycrystalline lead zirconate (PbZrO3) was studied. The single phase polycrystalline sample remained orthorhombic and antiferroelectric down to 20 K as... (Read more)
- 646. Phys. Rev. B 73, 174103 (2006) , “Electron-trapping centers and interstitials in chlorinated SrCl2:Fe single crystals”, D. Ghica, S. V. Nistor, E. Goovaerts, D. Schoemaker, H. Vrielinck, and F. CallensElectron-trapped Fe+-type centers, produced by x-ray irradiation at 80 K and further annealing at higher temperatures in iron-doped SrCl2 single crystals grown in chlorine gas, have been investigated by electron paramagnetic resonance. The Fe+(III) and... (Read more)
- 647. Phys. Rev. B 73, 165212 (2006) , “Identification of donor-related impurities in ZnO using photoluminescence and radiotracer techniques”, Karl Johnston, Martin O. Henry, Deirdre McCabe, Enda McGlynn, Marc Dietrich, Eduardo Alves, and Matthew XiaThe results of photoluminescence measurements on ZnO implanted with stable and radioactive isotopes of Zn and Ga are presented. The donor-related exciton feature I8 at 3.3600 eV is suggested to be due to bound exciton recombination at Ga donors. The I1 line at... (Read more)
- 648. Phys. Rev. B 73, 165209 (2006) , “Vacancy-impurity pairs in relaxed Si1–xGex layers studied by positron annihilation spectroscopy”, M. Rummukainen, J. Slotte, K. Saarinen, H. H. Radamson, J. Hållstedt, and A. Yu. KuznetsovPositron annihilation spectroscopy was applied to study relaxed P-doped n-type and undoped Si1xGex layers with x up to 0.30. The as-grown SiGe layers were found to be defect free and annihilation parameters in a random SiGe alloy could be... (Read more)
- 649. Phys. Rev. B 73, 165202 (2006) , “Radiation damage in silicon exposed to high-energy protons”, Gordon Davies, Shusaku Hayama, Leonid Murin, Reinhard Krause-Rehberg, Vladimir Bondarenko, Asmita Sengupta, Cinzia Davia, and Anna KarpenkoPhotoluminescence, infrared absorption, positron annihilation, and deep-level transient spectroscopy (DLTS) have been used to investigate the radiation damage produced by 24 GeV/c protons in crystalline silicon. The irradiation doses and the concentrations of carbon and oxygen in the samples... (Read more)
- 650. Phys. Rev. B 73, 161201(R) (2006) , “Thermally stable carbon-related centers in 6H-SiC: Photoluminescence spectra and microscopic models”, A. Mattausch, M. Bockstedte, O. Pankratov, J. W. Steeds, S. Furkert, J. M. Hayes, W. Sullivan, N. G. WrightRecent ab initio calculations [Mattausch et al., Phys. Rev. B 70, 235211 (2004)] of carbon clusters in SiC reveal a possible connection between the tricarbon antisite (C3)Si and the U photoluminescence center in 6H-SiC [Evans et al., Phys. Rev. B 66, 35204... (Read more)
- 651. Phys. Rev. B 73, 134112 (2006) , “EPR g-tensor of paramagnetic centers in yttria-stabilized zirconia from first-principles calculations”, F. Pietrucci, M. Bernasconi, C. Di Valentin, F. Mauri, and C. J. PickardIn order to assign the defect responsible for the experimental electron paramagnetic resonance (EPR) signal with trigonal symmetry (T center), we have studied the properties of different paramagnetic centers in yttria-stabilized cubic zirconia by computing the EPR g-tensor from density... (Read more)
- 652. Phys. Rev. B 73, 125206 (2006) , “Atomistic simulations on the thermal stability of the antisite pair in 3C- and 4H-SiC”, M. Posselt, F. Gao, W. J. WeberThe thermal stability of the first-neighbor antisite pair configurations in 3C- and 4H-SiC is investigated by atomic-level computer simulations. First, the structure and energetics of these defects are determined in order to check the accuracy of the interatomic potential employed. The results are... (Read more)
- 653. Phys. Rev. B 73, 125205 (2006) , “First-principles study of native defects in anatase TiO2”, Sutassana Na-Phattalung, M. F. Smith, Kwiseon Kim, Mao-Hua Du, Su-Huai Wei, S. B. Zhang, and Sukit LimpijumnongNative point defects in anatase TiO2 are investigated by using first-principles pseudopotential calculations based on density-functional theory (DFT). Antisite defects, namely, Ti-antisite (TiO) and O-antisite (OTi), have high formation energies and are hence... (Read more)
- 654. Phys. Rev. B 73, 125204 (2006) , “Optically detected magnetic resonance studies of point defects in Ga(Al)NAs”, I. P. Vorona, T.Mchedlidze, D. Dagnelund, I. A. Buyanova, W. M. Chen, K. KhlerAn optically detected magnetic resonance (ODMR) study of Ga(Al)NAs alloys grown by molecular beam epitaxy on GaAs substrates is presented. A number of grown-in defects were observed which act as nonradiative recombination centers. A detailed analysis of experimental data using a spin Hamiltonian... (Read more)
- 655. Phys. Rev. B 73, 125203 (2006) , “Origin of brown coloration in diamond”, L. S. Hounsome, R. Jones, P. M. Martineau, D. Fisher, M. J. Shaw, P. R. Briddon, and S. ÖbergMeasurements of the absorption spectra of brown natural type IIa diamond as well as brown nitrogen-doped CVD diamond are reported. These are largely featureless and increase almost monotonically from about 15.5 eV. It is argued that the brown coloration is due to an extended defect and not to... (Read more)
- 656. Phys. Rev. B 73, 121306 (2006) , “Resistively detected NMR in a two-dimensional electron system near mu = 1: Clues to the origin of the dispersive lineshape”, L. A. Tracy, J. P. Eisenstein, L. N. Pfeiffer, and K. W. WestResistively detected nuclear magnetic resonance (NMR) measurements on 2D electron systems near the =1 quantum Hall state are reported. In contrast to recent results of Gervais et al. [Phys. Rev. Lett. 94, 196803 (2005)], a dispersive line shape is found at all radio-frequency powers studied... (Read more)
- 657. Phys. Rev. B 73, 115208 (2006) , “Evidence for a trigonal dimer of antibonding hydrogen in crystalline silicon”, R. N. Pereira and B. Bech NielsenThe infrared absorption spectra recorded on silicon crystals implanted with protons at cryogenic temperatures reveal three lines at 812, 1608, and 1791 cm1, which originate from the excitation of local vibrational modes of a H defect. Measurements carried out on crystals subjected... (Read more)
- 658. Phys. Rev. B 73, 115207 (2006) , “First-principles study of migration mechanisms and diffusion of oxygen in zinc oxide”, Paul Erhart and Karsten AlbeWe have performed density-functional theory calculations in conjunction with the climbing image nudged elastic band method in order to study the self-diffusion of oxygen in zinc oxide. To this end, we have derived the complete set of migration paths for vacancies as well as interstitials in wurtzite... (Read more)
- 659. Phys. Rev. B 73, 115204 (2006) , “Platelets and the 110a0/4 {001} stacking fault in diamond”, J. P. Goss, P. R. Briddon, R. Jones, M. I. HeggieElectron microscopy reveals the presence of {001} platelets in annealed, nitrogen containing diamond. These extended planar defects give rise to a large displacement of the surrounding material, are correlated with luminescence and optical absorption, and are characterized by the B... (Read more)
- 660. Phys. Rev. B 73, 115203 (2006) , “Thermal stability of gamma-irradiation-induced oxygen-deficient centers in silica”, S. Agnello and L. NuccioThe effects of isochronal thermal treatments on three -irradiation-induced point defects, named the E, ODC(II), and H(I) centers, are investigated in various types of commercial silica (a-SiO2). ODC(II) is investigated by means of photoluminescence spectroscopy,... (Read more)
- 661. Phys. Rev. B 73, 115202 (2006) , “Annealing of electron-, proton-, and ion-produced vacancies in Si”, S. Dannefaer, V. Avalos, D. Kerr, R. Poirier, V. Shmarovoz, and S. H. ZhangPositron lifetime and Doppler measurements were performed on float-zone-refined and variously doped Czochralski-grown Si. The samples were irradiated by various particles (e, p, Kr) with energies between 2 MeV and 245 MeV. Electron or proton irradiation gave rise to... (Read more)
- 662. Phys. Rev. B 73, 113202 (2006) , “Demonstration of the effect of uniaxial stress on the electronic structure of bond-centered muonium in Si”, K. H. Chow, B. Hitti, and J. S. LordWe demonstrate that compressive uniaxial stress modifies the electronic structure of bond-centered muonium (MuBC0" align="middle">) in Si. The stress was applied along the 100 direction of the sample and results in a significant change in the hyperfine parameters of... (Read more)
- 663. Phys. Rev. B 73, 085204 (2006) , “Theory of boron aggregates in diamond: First-principles calculations”, J. P. Goss and P. R. BriddonIt is well known that nitrogen forms aggregates in diamond. However, little is known regarding aggregation of boron, an impurity that can be incorporated in very high concentrations. In this paper we present the results of first-principles calculations regarding the structure and properties of... (Read more)
- 664. Phys. Rev. B 73, 081203(R) (2006) , “Muonium in InSb: Shallow acceptor versus deep trap or recombination center”, V. G. Storchak, D. G. Eshchenko, J. H. Brewer, S. P. Cottrell, and R. L. LichtiThe bound state of a muonium atom has been detected in both n-type and p-type InSb using a high-field µSR technique. The hyperfine constant obtained for this isotropic center (AT=2464±1 MHz), roughly half that of a Mu atom in vacuum, is... (Read more)
- 665. Phys. Rev. B 73, 075201 (2006) , “Electron paramagnetic resonance and theoretical studies of shallow phosphorous centers in 3C-, 4H-, and 6H-SiC”, N. T. Son, A. Henry, J. Isoya, M. Katagiri, T. Umeda, A. Gali, E. JanznContinuous-wave (cw) electron paramagnetic resonance (EPR) at both X-band and W-band frequencies, pulsed-EPR, and pulsed electron nuclear double resonance (ENDOR) were used to study phosphorus shallow donors in 3C-, 4H-, and 6H-SiC doped with phosphorus (P) during... (Read more)
- 666. Phys. Rev. B 73, 073302 (2006) , “Origin of Pb1 center at SiO2/Si(100) interface: First-principles calculations”, K. Kato, T. Yamasaki, T. UdaBased on first-principles calculations, we studied the generation behavior of Pb centers at SiO2/Si interfaces, especially for Pb1 centers, under oxidation of Si(100) surfaces. Pb1 centers were found to be formed... (Read more)
- 667. Phys. Rev. B 73, 045208 (2006) , “Characterization of Eδ and triplet point defects in oxygen-deficient amorphous silicon dioxide”, G. Buscarino, S. Agnello, and F. M. GelardiWe report an experimental study by electron paramagnetic resonance (EPR) of γ-ray irradiation induced point defects in oxygen deficient amorphous SiO2 materials. We have found that three intrinsic (Eγ, Eδ, and triplet) and one... (Read more)
- 668. Phys. Rev. B 73, 033204 (2006) , “Electrical characterization of metastable carbon clusters in SiC: A theoretical study”, A. Gali, N. T. Son, E. JanznFirst-principles calculations carried out in 3C- and 4H-SiC show that small metastable carbon clusters can be created in irradiated SiC. The metastable carbon clusters possess occupation levels in the p-type as well as in the n-type 4H-SiC. Depending on the... (Read more)
- 669. Phys. Rev. B 73, 024117 (2006) , “Defect properties and p-type doping efficiency in phosphorus-doped ZnO”, Woo-Jin Lee, Joongoo Kang, and K. J. ChangBased on first-principles pseudopotential calculations, we investigated the electronic structure of various P-related defects in ZnO and the p-type doping efficiency for two forms of P dopant sources such as P2O5 and Zn3P2. As compared to N dopants,... (Read more)
- 670. Phys. Rev. B 73, 014111 (2006) , “Structure of SiO2/4H-SiC interface probed by positron annihilation spectroscopy”, M. Maekawa, A. Kawasuso, M. Yoshikawa, A. Miyashita, R. Suzuki, T. OhdairaThe structure of the SiO2/4H-SiC interface produced by dry oxidation has been studied using positron annihilation spectroscopy using energy-variable slow positron beams. Based on the Doppler broadening shape and wing parameter (S-W) correlation, the interface layer was... (Read more)
- 671. Phys. Rev. Lett. 97, 256603 (2006) , “Spatial Extent of Wave Functions of Gate-Induced Hole Carriers in Pentacene Field-Effect Devices as Investigated by Electron Spin Resonance”, Kazuhiro Marumoto, Shin-ichi Kuroda, Taishi Takenobu,, and Yoshihiro IwasaAn electron spin resonance (ESR) method is applied to a pentacene field-effect device to investigate gate-induced hole carriers in such devices. Clear field-induced ESR signals are observed, demonstrating that all of the field-injected carriers have S=1/2 spins. Anisotropic ESR signals due to... (Read more)
- 672. Phys. Rev. Lett. 97, 256602 (2006) , “Bistability-Mediated Carrier Recombination at Light-Induced Boron-Oxygen Complexes in Silicon”, Mao-Hua Du, Howard M. Branz, Richard S. Crandall, and S. B. ZhangA first-principles study of the BO2 complex in B-doped Czochralski Si reveals a defect-bistability-mediated carrier recombination mechanism, which contrasts with the standard fixed-level Shockley-Read-Hall model of recombination. An O2 dimer distant from B causes only weak... (Read more)
- 673. Phys. Rev. Lett. 97, 255902 (2006) , “Atomistic Mechanism of Boron Diffusion in Silicon”, Davide De Salvador, Enrico Napolitani, Salvatore Mirabella, Gabriele Bisognin, Giuliana Impellizzeri, Alberto Carnera, and Francesco PrioloB diffuses in crystalline Si by reacting with a Si self-interstitial (I) with a frequency g and so forming a fast migrating BI complex that can migrate for an average length λ. We experimentally demonstrate that both g and λ strongly depend on the free hole... (Read more)
- 674. Phys. Rev. Lett. 97, 227401 (2006) , “Optical Detection and Ionization of Donors in Specific Electronic and Nuclear Spin States”, A. Yang, M. Steger, D. Karaiskaj, M. L. W. Thewalt, M. Cardona, K. M. Itoh, H. Riemann, N. V. Abrosimov, M. F. Churbanov, A. V. Gusev, A. D. Bulanov, A. K. Kaliteevskii, O. N. Godisov, P. Becker, H.-J. Pohl, J. W. Ager III, and E. E. HallerWe resolve the remarkably sharp bound exciton transitions of highly enriched 28Si using a single-frequency laser and photoluminescence excitation spectroscopy, as well as photocurrent spectroscopy. Well-resolved doublets in the spectrum of the 31P donor reflect the hyperfine... (Read more)
- 675. Phys. Rev. Lett. 97, 226401 (2006) , “Quasiparticle Corrections to the Electronic Properties of Anion Vacancies at GaAs(110) and InP(110)”, Magnus Hedström, Arno Schindlmayr, Günther Schwarz, and Matthias SchefflerWe propose a new method for calculating optical defect levels and thermodynamic charge-transition levels of point defects in semiconductors, which includes quasiparticle corrections to the Kohn-Sham eigenvalues of density-functional theory. Its applicability is demonstrated for anion vacancies at... (Read more)
- 676. Phys. Rev. Lett. 97, 176404 (2006) , “Stark Tuning of Donor Electron Spins in Silicon”, F. R. Bradbury, A. M. Tyryshkin, Guillaume Sabouret, Jeff Bokor, Thomas Schenkel, and S. A. LyonWe report Stark shift measurements for 121Sb donor electron spins in silicon using pulsed electron spin resonance. Interdigitated metal gates on a Sb-implanted 28Si epilayer are used to apply the electric fields. Two quadratic Stark effects are resolved: a decrease of the... (Read more)
- 677. Phys. Rev. Lett. 97, 166803 (2006) , “Electronic Structure of Defect States in Hydroxylated and Reduced Rutile TiO2(110) Surfaces”, Cristiana Di Valentin, Gianfranco Pacchioni, and Annabella SelloniIt has been experimentally observed that a bridging oxygen vacancy on the rutile TiO2(110) surface introduces localized Ti3+ 3d1 states about 1 eV below the conduction band which are not removed upon dissociation of a water molecule and formation of a pair of... (Read more)
- 678. Phys. Rev. Lett. 97, 166402 (2006) , “Phosphorus Donors in Highly Strained Silicon”, Hans Huebl, Andre R. Stegner, Martin Stutzmann, Martin S. Brandt, Guenther Vogg, Frank Bensch, Eva Rauls, and Uwe GerstmannThe hyperfine interaction of phosphorus donors in fully strained Si thin films grown on virtual Si1-xGex substrates with x0.3 is determined via electrically detected magnetic resonance. For highly strained epilayers, hyperfine interactions as low as 0.8 mT... (Read more)
- 679. Phys. Rev. Lett. 97, 155901 (2006) , “Proton Diffusion Mechanism in Amorphous SiO2”, Julien Godet and Alfredo PasquarelloWe study proton diffusion in amorphous SiO2 from the atomic scale to the long-range percolative regime. Ab initio molecular dynamics suggest that the dominant atomic process consists in cross-ring interoxygen hopping assisted by network vibrations. A statistical analysis accounting... (Read more)
- 680. Phys. Rev. Lett. 97, 137206 (2006) , “Electron Spin Resonance of Proton-Irradiated Graphite”, Kyu Won Lee and Cheol Eui LeeIn the case of colossal magnetoresistance in the perovskite manganites, "double exchange" mediated by the itinerant spins is believed to play a key role in the ferromagnetism. In contrast, the conventional "Heisenberg" interaction, i.e., direct (unmediated) interaction between... (Read more)
- 681. Phys. Rev. Lett. 97, 135901 (2006) , “Vacancy-Assisted Diffusion in Silicon: A Three-Temperature-Regime Model”, Damien Caliste and Pascal PochetIn this Letter we report kinetic lattice Monte Carlo simulations of vacancy-assisted diffusion in silicon. We show that the observed temperature dependence for vacancy migration energy is explained by the existence of three diffusion regimes for divacancies. This characteristic has been rationalized... (Read more)
- 682. Phys. Rev. Lett. 97, 135502 (2006) , “29Si Hyperfine Structure of the Eα Center in Amorphous Silicon Dioxide”, G. Buscarino, S. Agnello, and F. M. GelardiWe report a study by electron paramagnetic resonance on the Eα point defect in amorphous silicon dioxide (a-SiO2). Our experiments were performed on γ-ray irradiated oxygen-deficient materials and pointed out that the 29Si... (Read more)
- 683. Phys. Rev. Lett. 97, 116101 (2006) , “Oxygen Migration, Agglomeration, and Trapping: Key Factors for the Morphology of the Si-SiO2 Interface”, L. Tsetseris and S. T. PantelidesThe measured activation energies for oxide growth rates at the initial and late stages of oxidation of Si are 2 and 1.2 eV, respectively. These values imply that oxidation can proceed at temperatures much smaller than the 800 °C normally used to obtain devices with exceptionally smooth... (Read more)
- 684. Phys. Rev. Lett. 97, 106802 (2006) , “Role of Pr Segregation in Acceptor-State Formation at ZnO Grain Boundaries”, Yukio Sato, James P. Buban, Teruyasu Mizoguchi, Naoya Shibata, Masatada Yodogawa, Takahisa Yamamoto, and Yuichi IkuharaThe role of Pr doping on double Schottky barrier formations at ZnO single grain boundaries was investigated by the combination of current-voltage measurements, atomic-resolution Z-contrast scanning transmission electron microscopy, and first-principles calculations. Although Pr segregated to... (Read more)
- 685. Phys. Rev. Lett. 97, 106402 (2006) , “E Center in Silicon Has a Donor Level in the Band Gap”, A. Nylandsted Larsen, A. Mesli, K. Bonde Nielsen, H. Kortegaard Nielsen, L. Dobaczewski, J. Adey, R. Jones, D. W. Palmer, P. R. Briddon, and S. ÖbergIt has been an accepted fact for more than 40 years that the E center in Si (the group-V impurityvacancy pair)one of the most studied defects in semiconductorshas only one energy level in the band gap: namely, the acceptor level at about 0.45 eV below the conduction... (Read more)
- 686. Phys. Rev. Lett. 97, 087601 (2006) , “Polarization and Readout of Coupled Single Spins in Diamond”, R. Hanson, F. M. Mendoza, R. J. Epstein, and D. D. AwschalomWe study the coupling of a single nitrogen-vacancy center in diamond to a nearby single nitrogen defect at room temperature. The magnetic dipolar coupling leads to a splitting in the electron spin resonance frequency of the nitrogen-vacancy center, allowing readout of the state of a single nitrogen... (Read more)
- 687. Phys. Rev. Lett. 97, 066602 (2006) , “Electrically Detected Electron Spin Resonance in a High-Mobility Silicon Quantum Well”, Junya Matsunami, Mitsuaki Ooya, and Tohru OkamotoThe resistivity change due to electron spin resonance (ESR) absorption is investigated in a high-mobility two-dimensional electron system formed in a Si/SiGe heterostructure. Results for a specific Landau level configuration demonstrate that the primary cause of the ESR signal is a reduction of the... (Read more)
- 688. Phys. Rev. Lett. 97, 066101 (2006) , “Structure and Interconversion of Oxygen-Vacancy-Related Defects on Amorphous Silica”, Chin-Lung Kuo and Gyeong S. HwangAtomic structure and structural stability of neutral oxygen vacancies on amorphous silica are investigated using combined Monte Carlo and density functional calculations. We find that, unlike their bulk counterparts, the Si-Si dimer configuration of surface oxygen vacancies is likely to be unstable... (Read more)
- 689. Phys. Rev. Lett. 97, 016102 (2006) , “Scaling and Universality of Roughening in Thermal Oxidation of Si(001)”, Hiroo Omi, Hiroyuki Kageshima, and Masashi UematsuBy analyzing atomic force microscopy images, we derive a continuum equation that quantitatively explains the roughening at the Si(001)-SiO2 interface during thermal oxidation at the temperature at 1200 °C in an Ar atmosphere containing a small fraction of O2. We also show... (Read more)
- 690. Phys. Rev. Lett. 96, 55501 (2006) , “Divacancy in 4H-SiC”, N. T. Son, P. Carlsson, J. ul Hassan, E. Janzn, T. Umeda, J. Isoya, A. Gali, M. Bockstedte, N. Morishita, T. Ohshima, H. ItohElectron paramagnetic resonance and ab initio supercell calculations suggest that the P6/P7 centers, which were previously assigned to the photoexcited triplet states of the carbon vacancy-antisite pairs in the double positive charge state, are related to the triplet ground... (Read more)
- 691. Phys. Rev. Lett. 96, 205504 (2006) , “First-Principles Study of the Diffusion of Hydrogen in ZnO”, M. G. Wardle, J. P. Goss, and P. R. BriddonZinc oxide, a wide-gap semiconductor, typically exhibits n-type conductivity even when nominally undoped. The nature of the donor is contentious, but hydrogen is a prime candidate. We present ab initio calculations of the migration barrier for H, yielding a barrier of less than ~0.5 ... (Read more)
- 692. Phys. Rev. Lett. 96, 196402 (2006) , “Nitrogen Vacancies as Major Point Defects in Gallium Nitride”, M. G. Ganchenkova and R. M. NieminenWe present results of ab initio calculations for vacancies and divacancies in GaN. Particular attention is paid to nitrogen vacancies and mixed Ga-N divacancies in negatively charged states, which in n-type GaN are found to be energetically comparable with gallium vacancies. We also... (Read more)
- 693. Phys. Rev. Lett. 96, 17203 (2006) , “Magnetic Anisotropy of Co2+ as Signature of Intrinsic Ferromagnetism in ZnO:Co”, P. Sati, R. Hayn, R. Kuzian, S. Régnier, S. Schäfer, A. Stepanov, C. Morhain, C. Deparis, M. Laügt, M. Goiran, and Z. GolackiWe report on the magnetic properties of thoroughly characterized Zn1-xCoxO epitaxial thin films, with low Co concentration, x=0.0030.005. Magnetic and EPR measurements, combined with crystal field theory, reveal that isolated Co2+ ions in... (Read more)
- 694. Phys. Rev. Lett. 96, 145501 (2006) , “Identification of the Carbon Antisite-Vacancy Pair in 4H-SiC”, T. Umeda, N. T. Son, J. Isoya, E. Janzn, T. Ohshima, N. Morishita, H. Itoh, A. Gali, M. BockstedteThe metastability of vacancies was theoretically predicted for several compound semiconductors alongside their transformation into the antisite-vacancy pair counterpart; however, no experiment to date has unambiguously confirmed the existence of antisite-vacancy pairs. Using electron paramagnetic resonance and first principles calculations we identify the SI5 center as the carbon antisite-vacancy pair in the negative charge state (CSiVC-) in 4H-SiC. We suggest that this defect is a strong carrier-compensating center in n-type or high-purity semi-insulating SiC. (Read more)SiC| ENDOR EPR Theory electron-irradiation optical-spectroscopy thermal-meas./anneal-exp.| -1 -2 1.0eV~ 13C 29Si C1h C3v Carbon Csi EI5/6 HEI1 HEI5/6 Nitrogen P6/7 SI5 Silicon Vc antisite bistable/metastable dangling-bond n-type pair(=2) semi-insulating vacancy .inp files: SiC/SI5_C1h SiC/SI5_80K SiC/SI5_100K | last update: Takashi Fukushima
- 695. Phys. Rev. Lett. 96, 035505 (2006) , “Mutual Passivation of Donors and Isovalent Nitrogen in GaAs”, Jingbo Li, Pierre Carrier, Su-Huai Wei, Shu-Shen Li, and Jian-Bai XiaWe study the mutual passivation of shallow donor and isovalent N in GaAs. We find that all the donor impurities, SiGa, GeGa, SAs, and SeAs, bind to N in GaAs:N, which has a large N-induced band-gap reduction relative to GaAs. For a group-IV impurity such... (Read more)
- 696. Physica B 376-377, 486 (2006) , “Preferential substitution of Fe on physically equivalent Ga sites in GaN”, W. Gehlhoff, D. Azamat, U. Haboeck, A. HoffmannThe EPR spectra of Fe3+ in high-quality thick freestanding hydride vapor phase grown GaN have been studied in the X- and Q-band. A complex resonance pattern with numerous lines of different intensities provided by three different defects is observed for these nearly stress-free iron-doped samples.... (Read more)
- 697. Physica B 376-377, 358-361 (2006) , “Pulsed EPR studies of Phosphorus shallow donors in diamond and SiC”, J. Isoya, M. Katagiri, T. Umeda, S. Koizumi, H. Kanda, N. T. Son, A. Henry, A. Gali, E. JanznPhosphorus shallow donors having the symmetry lower than Td are studied by pulsed EPR. In diamond:P and 3C–SiC:P, the symmetry is lowered to D2d and the density of the donor wave function on the phosphorus atom exhibits a predominant p-character. In 4H–SiC:P with the site symmetry of... (Read more)
- 698. Physica B 376-377, 177 (2006) , Elsevier , “Micro-characterisation of Si wafers by high-pressure thermopower technique”, S.V. Ovsyannikov, V.V. Shchennikov Jr, N.A. Shaydarova, V. V. Shchennikov, A. Misiuk, D. Yang, I.V. Antonova, S.N. ShaminIn the present work a set of Czochralski-grown silicon wafers (Cz–Si) differently pre-treated (annealed at high temperatures in pressure medium, doped with nitrogen, implanted with high-energy hydrogen ions) has been characterised by high-pressure thermopower S technique in the phase transitions region (0-20GPa). The shifts were observed in pressure of semiconductor–metal phase transition Pt determined from the S(P) under pre-treatments. For the first time, correlation dependence has been established between high-pressure thermoelectric properties on the one hand and concentration of residual interstitial oxygen cO (which is always present in Cz–Si) on the other hand. The dependence exhibited a maximum of Pt near cO~9×1017cm-3. (Read more)
- 699. Physica B 373, 182-193 (2006) , “Electron–nuclear double resonance and dynamic nuclear polarization in GaAs in the regime of the quantum Hall effect”, E. Olshanetsky, J.D. Caldwell, A.E. Kovalev, C.R. Bowers, J.A. Simmons , J.L. RenoElectron spin resonance (ESR) and electron-nuclear double resonance experiments were performed in the 2D electron systems of GaAs/AlxGa1−xAs quantum well and heterojunction samples in the vicinity of the unity filling factor in the regime of the quantum Hall effect. As is well known, the ESR... (Read more)
- 700. Superlatt. Microstruct. 39, 247-256 (2006) , “Optical and morphological features of bulk and homoepitaxial ZnO”, R. Yakimova, G.R. Yazdi, N.T. Son, I. Ivanov, M. Syvjrvi, S. Sun, G. Tompa, A. Kuznetsov , B. SvenssonZnO substrate crystals from two different sources, and epitaxial layers have been studied by SEM, AFM, photoluminescence and EPR. Although fabricated by the same growth principle, i.e. the hydrothermal technique, the substrates differ in terms of purity and structural quality. In the PL spectra of... (Read more)
- 701. Thin Solid Films 496, 169-173 (2006) , “Green luminescence from Mn ions in ZnO–GeO2 glasses prepared by sol–gel method and their glass ceramics”, Tomoe Sanada, Kazuhiro Yamamoto, Noriyuki Wada , Kazuo KojimaZn2SiO4:Mn2+ is one of the green light luminants used for cathode ray tubes of televisions. Recently, optical materials emitting strong visible light under lower energy excitation have been expected. To obtain new luminants of high quality, we prepared Mn ion doped ZnO–GeO2 glasses and glass... (Read more)
- 702. AIP Conf. Proc. 772, 89 (2005) , “Deep states of Pt, Ir, and Os in Silicon Carbide”, Joachim Grillenberger, Ulrike Grossner, Bengt G. Svensson, Fanny Albrecht, Wolfgang Witthuhn, Rainer SielemannBand gap states of platinum, iridium, and osmium in 4H silicon carbide (SiC) are investigated with Deep Level Transient Spectroscopy (DLTS). A definite chemical assignment of band gap states to Pt, Ir, and Os was achieved by means of the radiotracer principle: the radioactive isotope... (Read more)
- 703. AIP Conf. Proc. 772, 147 (2005) , American Institute of Physics , “Deep levels in osmium doped p-type GaAs grown by metal organic chemical vapor deposition”, M. Zafar Iqbal, A. Majid, A. Dadgar, and D. BimbergResults of a preliminary study on deep level transient spectroscopy (DLTS) investigations of osmium (Os) impurity in p-type GaAs, introduced in situ during MOCVD crystal growth, are reported for the first time. Os is clearly shown to introduce two prominent deep levels in the lower half-bandgap of GaAs at energy positions Ev + 0.42 eV (OsA) and Ev + 0.72 eV (OsB). A minority-carrier emitting defect feature observed in the upper half-bandgap is shown to consist of a band of Os-related deep levels with a concentration significantly higher than that of the majority carrier emitting deep levels. Detailed data on the emission rate signatures and related parameters of the Os-related deep levels are reported. ©2005 American Institute of Physics (Read more)
- 704. AIP Conf. Proc. 772, 143 (2005) , American Institute of Physics , “Deep levels in Ruthenium doped p-type MOCVD GaAs”, A. Majid, M. Zafar Iqbal, A. Dadgar, and D. BimbergRuthenium is introduced into GaAs during epitaxial growth by MOCVD. Preliminary results of DLTS investigation of the defect states associated with this 4d transition-metal impurity are reported for the first time. At least three deep levels are identified with Ru in the lower half-bandgap of GaAs at energy positions Ev + 0.38 eV, Ev + 0.52 eV and Ev + 0.65 eV, the last with a relatively higher concentration than the first two. At least one Ru-related deep level is observed in the upper half-bandgap at Ec – 0.66 eV with a significantly high concentration. Emission rate signatures and associated characteristics of all these defect levels are reported. The Ev + 0.65 eV level is found to exhibit an electric field dependent thermal emission characteristic. ©2005 American Institute of Physics (Read more)
- 705. AIP Conf. Proc. 772, 121 (2005) , “ESR Study of Zn-codoping Effect on the Luminescence Efficiency of the Er-2O Center in GaAs:Er,O”, M. Yoshida, K. Hiraka, H. Ohta, Y. Fujiwara, A. Koizumi, and Y. TakedaESR measurements of Zn-codoped GaAs:Er,O have been performed at 9.49 GHz. Several anisotropic ESR signals (A, B, and C) are observed. We found that the intensity of the C center decreases together with the decrease of the PL intensity by increasing the doping amount of Zn, while the changes of the... (Read more)
- 706. Appl. Phys. Lett. 87, 262108 (2005) , “Fast-forming boron-oxygen-related recombination center in crystalline silicon”, Karsten Bothe and Jan SchmidtThe mechanism of a fast carrier lifetime degradation effect proceeding within seconds in boron-doped Czochralski silicon is investigated. The decrease in the carrier lifetime is attributed to the formation of a deep boron-oxygen-related recombination center with a strongly asymmetric... (Read more)
- 707. Appl. Phys. Lett. 87, 261909 (2005) , “Generation of single color centers by focused nitrogen implantation”, J. Meijer and B. BurchardSingle defect centers in diamond have been generated via nitrogen implantation. The defects have been investigated by single defect center fluorescence microscopy. Optical and electron paramagnetic resonance spectra unambiguously show that the produced defect is the nitrogen-vacancy color center. An... (Read more)
- 708. Appl. Phys. Lett. 87, 261907 (2005) , “Verification of the O–Si–N complex in plasma-enhanced chemical vapor deposition silicon oxynitride films”, S. Naskar, S. D. Wolter, C. A. Bower, B. R. Stoner, J. T. GlassSilicon oxynitride films were deposited using a plasma-enhanced chemical vapor deposition process. The bond configurations of the constituent atoms in the deposited film were analyzed using x-ray photoelectron spectroscopy. Analysis of the Si 2p spectra showed the presence of... (Read more)
- 709. Appl. Phys. Lett. 87, 252118 (2005) , “"EL2" revisited: Observation of metastable and stable energy levels of EL2 in semi-insulating GaAs”, D. Kabiraj, S. GhoshBy using a combination of detailed experimental studies, we identify the metastable and stable energy levels of EL2 in semi-insulating GaAs. These results are discussed in light of the recently proposed models for EL2 in GaAs. ©2005 American Institute of Physics ... (Read more)
- 710. Appl. Phys. Lett. 87, 252113 (2005) , “Electrical activation of the Fe2+/3+ trap in Fe-implanted InP”, B. FraboniWe have studied the electrical activation of the Fe2+/3+ trap in Fe-implanted InP by means of capacitance-voltage and deep level transient spectroscopy analyses. Five deep traps have been identified and we have characterized the concentration and depth distribution of the... (Read more)
- 711. Appl. Phys. Lett. 87, 252102 (2005) , “Photoluminescence study of Sb-doped p-type ZnO films by molecular-beam epitaxy”, F. X. Xiu, Z. Yang, L. J. Mandalapu, D. T. Zhao, and J. L. LiuWe investigated photoluminescence (PL) from reliable and reproducible Sb-doped p-type ZnO films grown on n-Si (100) by molecular-beam epitaxy. Well-resolved PL spectra were obtained from completely dopant-activated samples with hole concentrations above 1.0×1018 ... (Read more)
- 712. Appl. Phys. Lett. 87, 242903 (2005) , “Density of defect states of aluminum nitride grown on silicon and silicon carbide substrates at room temperature”, V. Ligatchev, Rusli, and Zhao PanDensity of defect states of aluminum nitride (AlN) films deposited by rf magnetron sputtering on 100-oriented silicon (Si) and 4H-silicon carbide (4H-SiC) have been investigated using the deep-level-transient-spectroscopy technique. The films were grown at room temperature with varying nitrogen flow... (Read more)
- 713. Appl. Phys. Lett. 87, 242106 (2005) , “Defect-driven inhomogeneities in Ni/4H–SiC Schottky barriers”, S. Tumakha, D. J. Ewing, L. M. Porter, Q. Wahab, X. Ma, T. S. Sudharshan, L. J. BrillsonNanoscale depth-resolved cathodoluminescence spectroscopy (DRCLS) of Ni diode arrays on 4H-SiC epitaxial wafers reveals a striking correspondence between deep level defects and electrical transport measurements on a diode-by-diode basis. Current-voltage measurements display both ideal and nonideal... (Read more)
- 714. Appl. Phys. Lett. 87, 242103 (2005) , “Deep-level transient spectroscopy of TiO2/CuInS2 heterojunctions”, Marian Nanu, Florence Boulch, Joop Schoonman, and Albert GoossensDeep-level transient spectroscopy (DLTS) has been used to measure the concentration and energy position of deep electronic states in CuInS2. Flat TiO2|CuInS2 heterojunctions as well as TiO2-CuInS2 nanocomposites have been investigated.... (Read more)
- 715. Appl. Phys. Lett. 87, 241906 (2005) , “Deep-ultraviolet micro-Raman investigation of surface defects in a 4H–SiC homoepitaxially grown film”, Takuro Tomita, Shigeki Matsuo, Tatsuya Okada, Tsunenobu Kimoto, Hiroyuki Matsunami, Takeshi Mitani, Shin-Ichi NakashimaThe structures of comet defects in a 4HSiC homoepitaxially grown film are investigated by deep-ultraviolet micro-Raman spectroscopy. Spatial distribution of the 4H- and 3CSiC is clearly distinguished both from the intensities of the folded longitudinal acoustic phonon mode and the peak... (Read more)
- 716. Appl. Phys. Lett. 87, 231905 (2005) , “Structure, stability, and diffusion of arsenic-silicon interstitial pairs”, Scott A. Harrison, Thomas F. Edgar, and Gyeong S. HwangRecent experimental studies [A. Ural, P. B. Griffin, and J. D. Plummer, J. Appl. Phys. 85, 6440 (1999); R. Kim, T. Hirose, T. Shano, H. Tsuji, and K. Taniguchi, Jpn. J. Appl. Phys. 41, 227 (2002); S. Solmi, M. Ferri, M. Bersani, D. Giubertoni, and V. Soncini, J. Appl. Phys. 94,... (Read more)
- 717. Appl. Phys. Lett. 87, 223111 (2005) , “Time-resolved photoluminescence from ZnO nanostructures”, W. M. Kwok, A. B. Djurii?, Y. H. Leung, W. K. Chan, D. L. PhillipsDifferent ZnO nanostructures (tetrapods, shells, rods, and highly faceted rods) were characterized by photoluminescence (PL) and time-resolved PL measurements. It was found that different nanostructures exhibit very different optical properties in terms of defect emission and decay times of the... (Read more)
- 718. Appl. Phys. Lett. 87, 222101 (2005) , “Trapping-detrapping defects in single crystal diamond films grown by chemical vapor deposition”, A. Balducci, Marco Marinelli, E. Milani, M. E. Morgada, G. Prestopino, M. Scoccia, A. Tucciarone, and G. Verona-RinatiHigh-quality single-crystal diamond films were homoepitaxially grown by chemical vapor deposition onto low cost high-pressure high-temperature diamond substrates. The transport properties of the obtained samples were studied by photoresponse characterization. Fast ultraviolet (5 ns) laser pulses at... (Read more)
- 719. Appl. Phys. Lett. 87, 221903 (2005) , “Oxygen segregation to dislocations in GaN”, M. E. Hawkridge and D. ChernsThe structure and composition of threading dislocations in GaN grown by hydride vapor phase epitaxy have been examined by electron microscopy. Transmission electron microscopy showed that the core structure of screw dislocations varied widely, alternating irregularly between open core... (Read more)
- 720. Appl. Phys. Lett. 87, 212501 (2005) , “Spin-dependent tunneling through high-k LaAlO3”, V. Garcia, M. Bibes, J.-L. Maurice, E. Jacquet, K. Bouzehouane, J.-P. Contour, A. BarthlmyWe report on the use of the LaAlO3 (LAO) high-k dielectric as a tunnel barrier in magnetic tunnel junctions. From tunnel magnetoresistance (TMR) measurements on epitaxial La2/3Sr1/3MnO3/LAO/La2/3Sr1/3MnO3 junctions,... (Read more)
- 721. Appl. Phys. Lett. 87, 212114 (2005) , “Doping of phosphorus in chemical-vapor-deposited silicon carbide layers: A theoretical study”, T. Hornos, A. Gali, R. P. Devaty, W. J. ChoykeAb initio supercell calculations have been carried out to investigate the doping of phosphorus in chemical-vapor-deposited (CVD) silicon carbide (SiC) layers. We simulated the CVD conditions by using the appropriate chemical potentials for hydrogen and phosphorus (P). We find that the site... (Read more)
- 722. Appl. Phys. Lett. 87, 211912 (2005) , “Deep-level emissions influenced by O and Zn implantations in ZnO”, Q. X. Zhao, P. Klason, M. Willander, H. M. Zhong, W. Lu, J. H. YangA set of bulk ZnO samples implanted with O and Zn at various densities were investigated by photoluminescence. The implantation concentration of O and Zn is varied between 1×1017/cm3 and 5×1019/cm3. The samples were thermally treated in an... (Read more)
- 723. Appl. Phys. Lett. 87, 204106 (2005) , “Direct observation of the structure of defect centers involved in the negative bias temperature instability”, J. P. Campbell and P. M. LenahanWe utilize a very sensitive electron paramagnetic resonance technique called spin-dependent recombination to observe and identify defect centers generated by modest negative bias and moderately elevated temperatures in fully processed p-channel metal-oxide-silicon field-effect transistors.... (Read more)
- 724. Appl. Phys. Lett. 87, 193110 (2005) , “Initial nitride formation at Si/3C–SiC(100)3×2 interface by oxynitridation”, C. Radtke, H. Enriquez, J. C. Arnault, P. Soukiassian, P. Moras, C. Crotti, P. PerfettiNitric oxide interaction with 3CSiC(100)3×2 and Si-3×2/3CSiC(100)3×2 surfaces is investigated by synchrotron radiation-based core level photoemission spectroscopy. At 25 °C, NO exposures result in oxynitride formation, while annealing at 1000 °C removes oxygen... (Read more)
- 725. Appl. Phys. Lett. 87, 182115 (2005) , “Traps in AlGaN/GaN/SiC heterostructures studied by deep level transient spectroscopy”, Z.-Q. Fang and D. C. LookAlGaN/GaN/SiC Schottky barrier diodes (SBDs), with and without Si3N4 passivation, have been characterized by temperature-dependent current-voltage and capacitance-voltage measurements, and deep level transient spectroscopy (DLTS). A dominant trap A1, with... (Read more)
- 726. Appl. Phys. Lett. 87, 172108 (2005) , “Production of native donors in ZnO by annealing at high temperature in Zn vapor”, L. E. Halliburton, N. C. Giles, N. Y. Garces, Ming Luo, Chunchuan Xu, Lihai Bai, L. A. BoatnerZinc oxide crystals grown by the seeded chemical vapor transport method have been annealed in zinc vapor at 1100 °C for 30 min. These thermochemical reduction treatments produce a deep red coloration in the crystals and increase their n-type electrical conductivity. Electron paramagnetic... (Read more)
- 727. Appl. Phys. Lett. 87, 172103 (2005) , “The antimony-vacancy defect in p-type germanium”, C. E. Lindberg, J. Lundsgaard Hansen, P. Bomholt, A. Mesli, K. Bonde Nielsen, and A. Nylandsted LarsenGe-n+p mesa diodes have been produced in 2-Ω cm single crystals using a molecular-beam epitaxy (MBE) process to grow the Sb-doped epitaxial Ge n+-top layer. The diodes are characterized by a leakage current at room temperature of... (Read more)
- 728. Appl. Phys. Lett. 87, 161906 (2005) , “Vacancy formation in GaAs under different equilibrium conditions”, V. Bondarenko, J. Gebauer, F. Redmann, and R. Krause-RehbergDefect properties of undoped semiinsulating and silicon doped n-type GaAs annealed at different arsenic vapor pressures have been studied by means of positron annihilation and Hall effect measurements. In both types of samples, formation of monovacancylike defects during annealing was... (Read more)
- 729. Appl. Phys. Lett. 87, 151909 (2005) , “Far-infrared absorption due to electronic transitions of N–O complexes in Czochralski-grown silicon crystals: Influence of nitrogen and oxygen concentration”, H. Ch. Alt and Y. V. GomeniukFourier-transform infrared absorption measurements have been carried out on nitrogen-doped Czochralski-grown silicon crystals after thermal annealing at 600 °C. The strength of the electronic transitions due to NO related shallow donors shows a square root dependence on the nitrogen... (Read more)
- 730. Appl. Phys. Lett. 87, 122102 (2005) , “Oxygen vacancies in ZnO”, Anderson Janotti and Chris G. Van de WalleThe electronic properties of ZnO have traditionally been explained by invoking intrinsic defects. In particular, the frequently observed unintentional n-type conductivity has often been attributed to oxygen vacancies. We report first-principles calculations showing that the oxygen vacancy... (Read more)
- 731. Appl. Phys. Lett. 87, 091910 (2005) , “Interaction of nitrogen with vacancy defects in N+-implanted ZnO studied using a slow positron beam”, Z. Q. Chen, M. Maekawa, and A. KawasusoZnO crystals were implanted with N+, O+, and Al+, and co-implanted with O+/N+ and Al+/N+ ions. Positron annihilation measurements indicate introduction of vacancy clusters upon implantation. In the N+-implanted... (Read more)
- 732. Appl. Phys. Lett. 87, 062105 (2005) , “Negative-U property of oxygen vacancy in cubic HfO2”, Y. P. Feng, A. T. L. Lim, M. F. LiOxygen vacancy in cubic HfO2 was investigated using first-principles calculation based on density functional theory and generalized gradient approximation. Five different charge states (V++, V+, V0, V, and... (Read more)
- 733. Appl. Phys. Lett. 87, 051911 (2005) , “The origin of n-type conductivity in undoped In2O3”, Takumi Tomita, Kazuyoshi Yamashita, and Yoshinori HayafujiThis study explores the origin of the native donor in undoped In2O3. The electronic structure of various point defects in In2O3 clusters is studied using the first-principles molecular orbital calculation. The results show that an oxygen vacancy cannot act... (Read more)
- 734. Appl. Phys. Lett. 87, 032107 (2005) , “Interface traps and dangling-bond defects in (100)Ge/HfO2”, V. V. Afanas'ev, Y. G. Fedorenko, and A. StesmansCombined electrical and electron spin resonance analysis reveals dramatic differences in the interface defect properties of the (100)Ge/GeOxNy/HfO2 and (100)Ge/GeO2 interfaces from the seemingly similar interfaces of (100)Si with the... (Read more)
- 735. Appl. Phys. Lett. 87, 022903 (2005) , “Electron spin resonance investigation of oxygen-vacancy-related defects in BaTiO3 thin films”, V. V. Laguta, A. M. Slipenyuk, I. P. Bykov, M. D. Glinchuk, M. Maglione, D. Michau, J. Rosa, L. JastrabikThe Ti3+ center, based on a regular Ti site perturbed by an oxygen vacancy (VO), is identified by electron spin resonance (ESR) in textured BaTiO3 films. The center shows tetragonal symmetry along cubic 100 axes with g-factors: g=1.997,... (Read more)
- 736. Appl. Phys. Lett. 86, 261906 (2005) , “Radiation-induced electron traps in Al0.14Ga0.86N by 1 MeV electron radiation”, Michael R. Hogsed and Yung Kee YeoElectrical properties of defects induced in n-type molecular-beam-epitaxial-grown Al0.14Ga0.86N are studied using deep-level transient spectroscopy (DLTS) to explore the radiation tolerance of AlGaN-based electronic and optoelectronic devices. It has been found that four... (Read more)
- 737. Appl. Phys. Lett. 86, 222110 (2005) , “Magnetic resonance signatures of grown-in defects in GaInNP alloys grown on a GaAs substrate”, I. P. Vorona, T. Mchedlidze, M. Izadifard, I. A. Buyanova, and W. M. ChenDilute-nitride Ga0.44In0.56NyP1y alloys with y=00.02, grown on a GaAs substrate using gas-source molecular beam epitaxy, are studied by the optically detected magnetic resonance (ODMR) technique. Grown-in paramagnetic... (Read more)
- 738. Appl. Phys. Lett. 86, 171102 (2005) , “Optical observation of donor-bound excitons in hydrogen-implanted ZnO”, J.-K. Lee and M. NastasiThe optical and structural properties of H or He implanted ZnO were investigated using low temperature photoluminescence (PL) and infrared spectroscopy (IR). H implantation is shown to influence the relative luminescence intensities of the donor bound excitons, enhancing the 3.361 eV peak, and... (Read more)
- 739. Appl. Phys. Lett. 86, 162109 (2005) , “Electronic transitions at defect states in Cz p-type silicon”, A. Castaldini, D. Cavalcoli, and A. CavalliniPoint and extended defects introduced in p-type Cz Si by oxygen precipitation and plastic deformation have been investigated with electrical and optical methods. Different materials (oxygen precipitated and/or deformed Cz Si and Fz Si) were examined in order to separate the role of oxygen... (Read more)
- 740. Appl. Phys. Lett. 86, 152111 (2005) , “Electrical characterization of Er- and Pr-implanted GaN films”, S. F. Song, W. D. Chen, Chunguang Zhang, Liufang Bian, and C. C. HsuHall, currentvoltage, and deep-level transient spectroscopy measurements were used to characterize the electrical properties of metalorganic chemical vapor deposition grown undoped, Er- and Pr-implanted GaN films. Only one deep level located at 0.270 eV below the conduction band was found in... (Read more)
- 741. Appl. Phys. Lett. 86, 143507 (2005) , “First-principles studies of the intrinsic effect of nitrogen atoms on reduction in gate leakage current through Hf-based high-k dielectrics”, N. Umezawa, K. Shiraishi, T. Ohno, H. Watanabe, T. Chikyow, K. Torii, K. Yamabe, K. Yamada, H. Kitajima, T. ArikadoThe atomistic effects of N atoms on the leakage current through HfO2 high-k gate dielectrics have been studied from first-principles calculations within the framework of a generalized gradient approximation (GGA). It has been found that the intrinsic effects of N atoms drastically... (Read more)
- 742. Appl. Phys. Lett. 86, 142107 (2005) , “Diffusion and dissociation mechanisms of vacancy-oxygen complex in silicon”, Masayuki Furuhashi and Kenji TaniguchiWe are examining diffusion mechanisms of the vacancy-oxygen complex (VO) in bulk Si using ab initio calculations based on a 64-atom supercell. We found two atomic mechanisms involved in the VO diffusion; one is caused by migration of an interstitial oxygen atom, another by migration of a... (Read more)
- 743. Appl. Phys. Lett. 86, 122104 (2005) , “Midgap levels in both n- and p-type 4H–SiC epilayers investigated by deep level transient spectroscopy”, K. Danno, T. Kimoto, and H. MatsunamiMidgap levels in n- and p-type 4HSiC epilayers have been investigated by deep level transient spectroscopy (DLTS). The EH6/7 center (Ec1.55 eV) is the dominant midgap level as observed in DLTS spectra for n-type epilayers. The activation... (Read more)
- 744. Appl. Phys. Lett. 86, 122102 (2005) , “Current transport property of n-GaN/n-6H–SiC heterojunction: Influence of interface states”, Y. Huang, X. D. Chen, S. Fung, C. D. Beling, C. C. Ling, X. Q. Dai, and M. H. XieHeterostructures of n-GaN/n-6HSiC grown by hydride vapor phase epitaxy (HVPE) and molecular-beam epitaxy (MBE) are characterized with the currentvoltage (IV), capacitancevoltage (CV), and deep level transient spectroscopy (DLTS)... (Read more)
- 745. Appl. Phys. Lett. 86, 102108 (2005) , “Activation of shallow boron acceptor in C/B coimplanted silicon carbide: A theoretical study”, A. Gali, T. Hornos, and P. DeákAb initio supercell calculations have been carried out to investigate the complexes of boron acceptors with carbon self-interstitials in cubic silicon carbide. Based on the calculated binding energies, the complex formation of carbon interstitials with shallow boron acceptor and boron... (Read more)
- 746. Appl. Phys. Lett. 86, 101905 (2005) , “Mechanisms of B deactivation contol by F co-implantation”, N.E.B.Cowern and B.Colombeau and J.Benson and A.J.smith and W.Lerch and S.Paul and T.Graf and F.Cristiano and X.Hebras and D.BolzeThermal annealing after preamorphization and solid-phase epitaxy of ultrashallow B implants leads to deactivation and diffusion driven by interstitials released from end-of-range defects. F inhibits these processes by forming small clusters that trap interstitials. A competing BF interaction... (Read more)
- 747. Appl. Phys. Lett. 86, 091903 (2005) , “Observation of recombination enhanced defect annealing in 4H–SiC”, L. Storasta, F. H. C. Carlsson, J. P. Bergman, and E. JanzénWe report observation of recombination enhanced defect annealing in 4HSiC detected by capacitance transient spectroscopy and low temperature photoluminescence (PL). Intrinsic defect centers, created by 160 keV electron irradiation, reduce in concentration after illumination at temperatures... (Read more)
- 748. Appl. Phys. Lett. 86, 081914 (2005) , “Photochromism of vacancy-related defects in thermochemically reduced α-Al2O3:Mg single crystals”, R. Ramírez, M. Tardío, and R. GonzálezOxygen vacancies and their aggregates are produced much more readily in Mg-doped α-Al2O3 than in undoped α-Al2O3 single crystals during thermochemical reduction at high temperatures. A reversible photochromic effect was discovered in Mg-doped... (Read more)
- 749. Appl. Phys. Lett. 86, 061914 (2005) , “Nondestructive characterization of dislocations and micropipes in high-resistivity 6H–SiC wafers by deep-level photoluminescence mapping”, M. Tajima, E. Higashi, T. Hayashi, H. Kinoshita, H. ShiomiWe demonstrated the effectiveness of deep-level photoluminescence (PL) mapping for nondestructive detection of dislocations and micropipes in high-resistivity 6HSiC wafers. PL spectra of the wafers at room temperature were dominated by a broad band with a peak at 1.3 eV, which was traceable... (Read more)
- 750. Appl. Phys. Lett. 86, 052109 (2005) , “Estimation of residual nitrogen concentration in semi-insulating 4H-SiC via low temperature photoluminescence”, E. R. Glaser, B. V. Shanabrook, and W. E. CarlosThe conditions and limitations are presented for using low-temperature photoluminescence to estimate the total residual nitrogen concentration in semi-insulating (SI) 4H-SiC substrates where all N shallow donors are compensated in the dark. The ratio of the nitrogen-bound exciton line... (Read more)
- 751. Appl. Phys. Lett. 86, 031915 (2005) , “Effect of growth polarity on vacancy defect and impurity incorporation in dislocation-free GaN”, F. Tuomisto and K. SaarinenWe have used positron annihilation, secondary ion mass spectrometry, and photoluminescence to study the point defects in GaN grown by hydride vapor phase epitaxy (HVPE) on GaN bulk crystals. The results show that N polar growth incorporates many more donor and acceptor type impurities and also Ga... (Read more)
- 752. Appl. Phys. Lett. 86, 031903 (2005) , “Anomalous behaviors of E1/E2 deep level defects in 6H silicon carbide”, X. D. Chen, C. C. Ling, M. Gong, S. Fung, C. D. Beling, G. Brauer, W. Anwand, W. SkorupaDeep level defects E1/E2 were observed in He-implanted, 0.3 and 1.7 MeV electron-irradiated n-type 6HSiC. Similar to others' results, the behaviors of E1 and E2 (like the peak intensity ratio, the annealing... (Read more)
- 753. Appl. Phys. Lett. 86, 023503 (2005) , “Observation of trapping defects in 4H–silicon carbide metal-oxide-semiconductor field-effect transistors by spin-dependent recombination”, David J. Meyer, Patrick M. Lenahan, Aivars J. LelisWe utilize a highly sensitive electron spin resonance technique called spin-dependent recombination to observe deep level dangling bond centers at and very near the SiC/SiO2 interface in fully processed n-channel 4HSiC lateral metal-oxide-semiconductor field-effect... (Read more)
- 754. Chem. Phys. Lett. 415, 337 (2005) , “No ferromagnetism in Mn doped ZnO semiconductors”, J. Alaria, P. Turek, M. Bernard, M. Bouloudenine, A. Berbadj, N. Brihi, G. Schmerber, S. Colis , A. DiniaPolycrystalline Zn1 − xMnxO was synthesized by co-precipitation method with xvarying between 0.01 and 0.10. Although X-ray diffraction patterns show a typical würtzite structure with no additional peaks for all samples, Raman spectroscopy indicates the appearance of an additional mode in... (Read more)
- 755. J. Appl. Phys. 98, 113524 (2005) , “Defect energy levels in hydrogen-implanted and electron-irradiated n-type 4H silicon carbide”, G. Alfieri, E. V. Monakhov, B. G. Svensson, A. HallnUsing deep level transient spectroscopy (DLTS), we have studied the energy position and thermal stability of deep levels in nitrogen doped 4HSiC epitaxial layers after 1.2 MeV proton implantation and 15 MeV electron irradiation. Isochronal annealing was performed at temperatures from 100 to... (Read more)
- 756. J. Appl. Phys. 98, 113506 (2005) , “Swelling of SiC under helium implantation”, S. Leclerc, A. Declémy, M. F. Beaufort, C. Tromas, and J. F. BarbotSingle crystals 4H-SiC were implanted with 50 keV helium ions at temperatures up to 600 °C and fluences in the range 1×10161×1017 cm2. The helium implantation-induced swelling was studied through the measurement of the step height. The... (Read more)
- 757. J. Appl. Phys. 98, 106108 (2005) , “Growth and characterization of SiC epitaxial layers on Si- and C-face 4H SiC substrates by chemical-vapor deposition”, Kodigala Subba Ramaiah, I. Bhat, T. P. Chow, J. K. Kim, E. F. Schubert, D. Johnstone, S. Akarca-BiyikliHigh-quality Schottky junctions have been fabricated on n-type 4H SiC epitaxial layers grown by chemical-vapor deposition on C- and Si-face substrates in order to understand the effect of growth direction on the growth mechanism and formation of defects. Atomic force microscopy... (Read more)
- 758. J. Appl. Phys. 98, 093701 (2005) , “Deep-level defects introduced by 1 MeV electron radiation in AlInGaP for multijunction space solar cells”, H. S. Lee and M. YamaguchiPresented in this paper are 1 MeV electron irradiation effects on wide-band-gap (1.97 eV) (Al0.08Ga0.92)0.52In0.48P diodes and solar cells. The carrier removal rate estimated in p-AlInGaP with electron fluence is about 1 cm1, which... (Read more)
- 759. J. Appl. Phys. 98, 093517 (2005) , “Large lattice relaxation deep levels in neutron-irradiated GaN”, S. Li, J. D. Zhang, C. D. Beling, K. Wang, and R. X. WangDeep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) measurements have been carried out in neutron-irradiated n-type hydride-vapor-phase-epitaxy-grown GaN. A defect center characterized by a DLTS line, labeled as N1, is observed at... (Read more)
- 760. J. Appl. Phys. 98, 083709 (2005) , American Institute of Physics , “Osmium impurity-related deep levels in n-type GaAs”, A. Majid, M. Zafar Iqbal, A. Dadgar and D. BimbergThe 5d transition-metal impurity, osmium, has been incorporated during the growth of n-type GaAs epitaxial layers using low-pressure metal-organic chemical-vapor deposition to characterize defect states associated with this heavy and, therefore, thermally stable dopant impurity.... (Read more)
- 761. J. Appl. Phys. 98, 073502 (2005) , “Origin of green luminescence in ZnO thin film grown by molecular-beam epitaxy”, Y. W. HeoThe properties of ZnO films grown by molecular-beam epitaxy are reported. The primary focus was on understanding the origin of deep-level luminescence. A shift in deep-level emission from green to yellow is observed with reduced Zn pressure during the growth. Photoluminescence and Hall measurements... (Read more)
- 762. J. Appl. Phys. 98, 053707 (2005) , “An asymmetry of conduction mechanisms and charge trapping in thin high-k HfxTiySizO films”, A. Paskaleva, A. J. Bauer, M. LembergerThe electrical behavior of high-permittivity (high-k) hafnium titanium silicate (HfxTiySizO) layers with different Hf:Ti ratios in the films is investigated. The films were deposited by metal-organic chemical-vapor deposition using a... (Read more)
- 763. J. Appl. Phys. 98, 053706 (2005) , “Deep levels by proton and electron irradiation in 4H–SiC”, Antonio Castaldini, Anna Cavallini, Lorenzo Rigutti, Filippo Nava, Sergio Ferrero, Fabrizio GiorgisThe effects on 4H-silicon carbide epilayers of irradiation with protons and electrons having particle energies, respectively, of 6.5 and 8.2 MeV were carefully studied and critically compared. In detail, the electronic levels associated with the irradiation-induced defects were analyzed by... (Read more)
- 764. J. Appl. Phys. 98, 053704 (2005) , “Impact of deep levels on the electrical conductivity and luminescence of gallium nitride codoped with carbon and silicon”, A. Armstrong and A. R. ArehartThe impact of C incorporation on the deep level spectrum of n-type and semi-insulating GaN:C:Si films grown by rf plasma-assisted molecular-beam epitaxy (MBE) was investigated by the combination of deep level transient spectroscopy, steady-state photocapacitance, and transient deep level... (Read more)
- 765. J. Appl. Phys. 98, 043709 (2005) , “Carrier compensation near tail region in aluminum- or boron-implanted 4H–SiC (0001)”, Y. Negoro, T. Kimoto, and H. MatsunamiElectrical behavior of implanted Al and B near implant-tail region in 4HSiC (0001) after high-temperature annealing has been investigated. Depth profiles of Al and B acceptors determined by capacitance-voltage characteristics are compared with those of Al and B atoms measured by... (Read more)
- 766. J. Appl. Phys. 98, 043518 (2005) , “Annealing behavior between room temperature and 2000 °C of deep level defects in electron-irradiated n-type 4H silicon carbide”, G. Alfieri, E. V. Monakhov, and B. G. SvenssonThe annealing behavior of irradiation-induced defects in 4H-SiC epitaxial layers grown by chemical-vapor deposition has been systematically studied by means of deep level transient spectroscopy (DLTS). The nitrogen-doped epitaxial layers have been irradiated with 15-MeV electrons at room temperature... (Read more)
- 767. J. Appl. Phys. 98, 043508 (2005) , “Deep-level defects in n-type 6H silicon carbide induced by He implantation”, C. C.Ling, X. D. Chen, G. Brauer, W. Anwand, W. Skorupa, H. Y. Wang, H. M. WengDefects in He-implanted n-type 6HSiC samples have been studied with deep-level transient spectroscopy. A deep-level defect was identified by an intensity with a logarithmical dependence on the filling pulse width, which is characteristic of dislocation defects. Combined with information... (Read more)
- 768. J. Appl. Phys. 98, 043507 (2005) , “Electric-dipole spin-resonance signals related to extended interstitial agglomerates in silicon”, T. MchedlidzeThree electric-dipole spin-resonance signals, labeled TU7, TU8, and TU9, were detected after subjecting oxygen-rich silicon samples to two-step annealing procedures at 450 and 650 °C for prolonged times. The formation and structural evolution of large interstitial agglomerates, known as rodlike... (Read more)
- 769. J. Appl. Phys. 98, 033704 (2005) , “N interstitial and its interaction with substitutional Mg in p-type GaN”, R. R. Wixom and A. F. WrightDensity-functional theory and the generalized gradient approximation were utilized to investigate the local-energy-minimum configurations and formation energies of N interstitials and their interaction with substitutional Mg in p-type GaN. Along with previously proposed configurations of the... (Read more)
- 770. J. Appl. Phys. 98, 023704 (2005) , “Charge trap levels in sulfur-doped chemical-vapor-deposited diamond with applications to ultraviolet dosimetry”, E. Trajkov and S. PrawerElectrically active defects and traps in sulfur-doped polycrystalline diamond films synthesized by microwave-assisted chemical-vapor deposition are evaluated using thermally stimulated conductivity measurements after ultraviolet (UV) illumination. The measurements are found to be consistent with the... (Read more)
- 771. J. Appl. Phys. 98, 013502 (2005) , “Near-band-edge slow luminescence in nominally undoped bulk ZnO”, T. Monteiro, A. J. Neves, M. C. Carmo, M. J. Soares, M. Peres, and J. WangWe report the observation of slow emission bands overlapped with the near-band-edge steady-state luminescence of nominally undoped ZnO crystals. At low temperatures the time-resolved spectra are dominated by the emission of several high-energy bound exciton lines and the two-electron satellite... (Read more)
- 772. J. Appl. Phys. 97, 23909 (2005) , “Electron spin resonance study of Zn-codoping effect on the local structure of the Er-related centers in GaAs:Er,O”, Makoto Yoshida, Kensaku Hiraka, Hitoshi Ohta, Yasufumi Fujiwara, Atsushi Koizumi, Yoshikazu TakedaElectron spin resonance (ESR) measurements of Zn-codoped GaAs:Er,O grown by organometallic vapor phase epitaxy have been performed at 9.49 GHz. Several anisotropic ESR signals (named as A, B, and C) are observed. The angular and temperature dependences of the A, B, and C signals are quite... (Read more)
- 773. J. Appl. Phys. 97, 124507 (2005) , “Electrical behavior of 4H-SiC metal-oxide-semiconductor structures with Al2O3 as gate dielectric”, A. Paskaleva, R. R. Ciechonski, M. Syvjrvi, E. Atanassova, R. YakimovaThe electrical properties of Al2O3 as a gate dielectric in metal-oxide-semiconductor structures based on n- and p-type 4H-SiC grown by sublimation method have been investigated and compared to the properties of similar structures utilizing SiO2. The... (Read more)
- 774. J. Appl. Phys. 97, 123905 (2005) , “Electron paramagnetic resonance of Cr3+ in near-stoichiometric LiTaO3”, M. Loyo-Menoyo and D. J. KeebleElectron-paramagnetic-resonance (EPR) experiments on the dominant Cr3+ center in near-stoichiometric LiTaO3 crystals, grown by the double crucible Czochralski method, are reported. A near complete roadmap of EPR positions was obtained allowing an accurate determination of the... (Read more)
- 775. J. Appl. Phys. 97, 123509 (2005) , “Observation of a spin one native defect in as-grown high-purity semi-insulating 4H SiC”, M. E. Zvanut, Haiyan Wang, Mpumelelo Richards, and V. V. KonovalovElectron paramagnetic resonance measurements of high-purity semi-insulating 4H SiC reveals a spectrum characteristic of an S=1 defect, which appears only after exposure to light with a wavelength less than 690 nm. Analysis of the hyperfine structure of the spectrum suggests that the defect is... (Read more)
- 776. J. Appl. Phys. 97, 123502 (2005) , “Ion irradiation of inhomogeneous Schottky barriers on silicon carbide”, F. Roccaforte, S. Libertino, F. Giannazzo, C. Bongiorno, F. La Via, and V. RaineriIn this paper, the effects of ion irradiation on Schottky barriers formed on silicon carbide are discussed. After Si-ion irradiation at the near-interface region in Ti/4H-SiC contacts an increase of the Schottky barrier height from 1.05 to 1.21 eV was observed, accompanied by a lowering of the... (Read more)
- 777. J. Appl. Phys. 97, 093517 (2005) , “Interaction of defects and H in proton-irradiated GaN(Mg, H)”, S. M. Myers and C. H. SeagerMagnesium-doped, p-type GaN containing H was irradiated with MeV protons at room temperature and then annealed at a succession of increasing temperatures, with the behavior of defects and H in the material being followed through infrared absorption spectroscopy, nuclear-reaction analysis of... (Read more)
- 778. J. Appl. Phys. 97, 084913 (2005) , “Bulk growth of high-purity 6H-SiC single crystals by halide chemical-vapor deposition”, H. J. Chung, A. Y. Polyakov, S. W. Huh, S. Nigam, and M. SkowronskiHigh-purity 6H-SiC single crystals were grown by the halide chemical-vapor deposition process. Growth was performed in a vertical hot-wall reactor with a separate injection of a silicon precursor (silicon tetrachloride) and a carbon precursor (propane). Typical growth rates were between 100 and 300 ... (Read more)
- 779. J. Appl. Phys. 97, 083529 (2005) , “A method to determine deep level profiles in highly compensated, wide band gap semiconductors”, A. Armstrong, A. R. Arehart, and S. A. RingelA lighted capacitancevoltage (LCV) method for spatially profiling defect levels in wide band gap, highly compensated materials is presented. Combined with deep level optical spectroscopy, the optical nature of the LCV profiling technique enables the quantitative study of lower bounds of... (Read more)
- 780. J. Appl. Phys. 97, 063511 (2005) , “Positron beam studies of argon-irradiated polycrystal α-Zr”, Chunlan ZhouDoppler broadening spectroscopy was performed using a variable-energy positron beam to investigate the effect of defects induced by 150-keV Ar-ion-irradiated α-Zr bulk material. S parameter in the damaged layer of the as-irradiated sample induced by ion irradiation increased with the... (Read more)
- 781. J. Appl. Phys. 97, 056101 (2005) , “Triplet recombination at Pb centers and its implications for capture cross sections”, Felice Friedrich, Christoph Boehme, and Klaus LipsPulsed electrically detected magnetic resonance measurements are presented showing that Pb centers at the crystalline silicon (c-Si) (111) to silicon dioxide (SiO2) interface can cause recombination of strongly coupled spin pairs in singlet and triplet... (Read more)
- 782. J. Appl. Phys. 97, 053704 (2005) , “The role of nitrogen-related defects in high-k dielectric oxides: Density-functional studies”, J. L. Gavartin, A. L. Shluger, A. S. Foster, G. I. BersukerUsing ab initio density-functional total energy and molecular-dynamics simulations, we study the effects of various forms of nitrogen postdeposition anneal (PDA) on the electric properties of hafnia in the context of its application as a gate dielectric in field-effect transistors. We... (Read more)
- 783. J. Appl. Phys. 97, 043504 (2005) , “Photoluminescence of mechanically polished ZnO”, D. W. Hamby, D. A. Lucca, and M. J. KlopfsteinThe effects of mechanical polishing on the photoluminescence (PL) from each polar face of wurtzite-structure ZnO are presented. Differences observed for the 4.2 K PL of a mechanically polished surface when compared to that of a chemomechanically polished surface include broadened bound-exciton... (Read more)
- 784. J. Appl. Phys. 97, 034302 (2005) , “Interfaces between 4H-SiC and SiO2: Microstructure, nanochemistry, and near-interface traps”, Eckhard Pippel, Jrg Woltersdorf, Halldor . lafsson, Einar . SveinbjrnssonWe report on electrical and microscopic investigations aimed to clarify the origin of near-interface traps (NITs) in metalsilicon dioxide4H-silicon carbide structures. Using capacitancevoltage and thermal dielectric relaxation current (TDRC) analysis we investigated NITs close to... (Read more)
- 785. J. Appl. Phys. 97, 033702 (2005) , “Recombination-induced athermal migration of hydrogen and deuterium in SiC”, Yaroslav Koshka and Bharat KrishnanThe phenomenon of recombination-induced formation of hydrogen-defect complexes in epitaxial silicon carbide (SiC) was further investigated on p-type samples treated in deuterium plasma. Qualitatively similar effects were observed for hydrogen and deuterium. The formation of hydrogen-related... (Read more)
- 786. J. Appl. Phys. 97, 033513 (2005) , “Fluence, flux, and implantation temperature dependence of ion-implantation-induced defect production in 4H–SiC”, J. Slotte, K. Saarinen, M. S. Janson, A. Halln, A. Yu. Kuznetsov, B. G. Svensson, J. Wong-Leung, C. JagadishVacancy-type defect production in Al- and Si-implanted 4HSiC has been studied as a function of ion fluence, ion flux, and implantation temperature in the projected ion range region by positron annihilation spectroscopy and Rutherford backscattering techniques. Ion channeling measurements show... (Read more)
- 787. J. Appl. Phys. 97, 023505 (2005) , “Nickel solubility in intrinsic and doped silicon”, A. A. Istratov and P. ZhangSolubility of nickel in intrinsic, moderately, and heavily doped n-type and p-type silicon was determined using instrumental neutron activation analysis. The solubility data for intrinsic silicon were found to be in good agreement with the literature data. In heavily doped... (Read more)
- 788. J. Appl. Phys. 97, 013540 (2005) , “Correlation between morphological defects, electron beam-induced current imaging, and the electrical properties of 4H–SiC Schottky diodes”, Y. Wang, G. N. Ali, M. K. Mikhov, V. Vaidyanathan, B. J. Skromme, B. Raghothamachar, M. DudleyDefects in SiC degrade the electrical properties and yield of devices made from this material. This article examines morphological defects in 4HSiC and defects visible in electron beam-induced current (EBIC) images and their effects on the electrical characteristics of Schottky diodes. Optical... (Read more)
- 789. J. Appl. Phys. 97, 013533 (2005) , “Observation of dislocations in diffused 4H–SiC p-i-n diodes by electron-beam induced current”, S. Maximenko, S. Soloviev, D. Cherednichenko, and T. SudarshanThe electron-beam induced current (EBIC) method was employed to investigate the electrical activity of dislocations in silicon-carbide-diffused p-n diodes. It was observed that EBIC contrast depends on the type of defect (superscrew, screw, and edge dislocation). This dependence was... (Read more)
- 790. J. Appl. Phys. 97, 013528 (2005) , “Production and recovery of defects in phosphorus-implanted ZnO”, Z. Q. Chen, A. Kawasuso, Y. Xu, and H. NaramotoPhosphorus ions were implanted in ZnO single crystals with energies of 50380 keV having total doses of 4.2×10134.2×1015 cm2. Positron annihilation measurements reveal the introduction of vacancy clusters after implantation. These... (Read more)
- 791. J. Chem. Phys. 122, 094508 (2005) , “Application of the Wolf damped Coulomb method to simulations of SiC”, Y. Ma and S. H. GarofaliniA multibody interatomic potential is developed for bulk SiC using a modification of the Wolf et al. summation technique [D. Wolf, P. Keblinski, S. R. Phillpot, and J. Eggebrecht, J. Chem. Phys. 110, 8254 (1999)] for the electrostatic interaction. The technique is modified to account for the... (Read more)
- 792. J. Magn. Magn. Mater. 302, 118 (2005) , “Magnetism origin of Mn-doped ZnO nanoclusters”, J.H. Li, D.Z. Shen, J.Y. Zhang, D.X. Zhao, B.S. Li, Y.M. Lu, Y.C. Liu , X.W. FanZnMnO nanoclusters were synthesized by the sol–gel method. The structural and magnetic characters were investigated. The XRD spectrum shows ZnMnO nanoclusters are hexagonal wurtzite structures and a small quantity of ZnMn2O4 phase is also present in the spectrum. The percentages of Zn and Mn... (Read more)
- 793. J. Phys.: Condens. Matter 17, S3179 (2005) , IOP Publishing , “Phase transitions in PbSe under actions of fast neutron bombardment and pressure”, S.V. Ovsyannikov, V.V. Shchennikov, A.E. Kar’kin, B.N. GoshchitskiiIn this paper, the influences of fast neutron bombardment, high pressure and chemical substitution on the electronic properties of PbSe single crystals are studied. For the first time in p-PbSe an electronic transition has been established of 'metal–semiconductor' type accompanied by an... (Read more)
- 794. J. Quant. Spectrosc. Radiat. Transfer 90, 97-113 (2005) , “Spectroscopic investigations on ZnF2–MO–TeO2 (MO=ZnO, CdO and PbO) glasses doped with chromium ions”, C. Laxmi Kanth, B. V. Raghavaiah, B. Appa Rao , N. VeeraiahDifferential scanning calorimetric studies, spectroscopic studies (viz., optical absorption, ESR, infrared spectra) and thermoluminescence studies of ZnF2–MO–TeO2 (MO=ZnO, CdO and PbO) glasses doped with different concentrations of chromium ions have been investigated. Results have... (Read more)
- 795. J. Vac. Sci. Technol. B 23, 594 (2005) , “Electronic defect states at annealed metal/4H–SiC interfaces”, S. Tumakha, S. H. Goss, L. J. Brillson, R. S. OkojieWe have used low energy electron-excited nanoscale luminescence spectroscopy (LEEN) to study the formation of electronic surface states at metal/4HSiC contacts. These junctions were formed using both low and high reactivity metals to study how the nature of interface chemical bonding affects... (Read more)
- 796. JETP Lett. 82, 441 (2005) , “EPR Identification of the Triplet Ground State and Photoinduced Population Inversion for a Si-C Divacancy in Silicon Carbide”, P. G. Baranov, I. V. Ilin, E. N. Mokhov, M V. Muzafarova, S. B. Orlinskii, J. Schmidt
- 797. Mater. Sci. Eng. B 124-125, 192 (2005) , “Effect of fluorine on boron thermal diffusion in the presence of point defects”, M.N.Kham and H.A.W.El Mubared and J.M.Bonar and P.AshuburnWith the increased interest in the use of fluorine co-implantation with boron for boron diffusion suppression in MOSFET devices, it is important to understand the mechanisms by which fluorine reduces boron diffusion. Mechanisms, such as B–F chemical reaction, vacancy–fluorine clusters and fluorine–interstitials interactions have been proposed in the literature. In this paper, a point defect injection is done to investigate the mechanism responsible for boron TED and thermal diffusion suppression in F+ and B+ implanted silicon. A 5 keV, 7 × 1012 cm-2 B+ implant into silicon is used which is typical for halo implants in n-MOS. Three F+ energies, 5, 50 and 185 keV, are used. It is followed by rapid thermal annealing at 900–1000 °C for different times in N2 for an inert anneal and O2 for injection of interstitial point defects from the surface. Fluorine profiles for samples implanted with 185 keV F+ and annealed in N2 show two fluorine peaks at ~Rpand~Rp/2. Under interstitial injection, the Rp/2 peak decreases in size and for long anneal times is completely eliminated, supporting an earlier claim that the Rp/2 peak is due to vacancy–fluorine clusters. The amount of suppression of both boron TED and thermal diffusion at 900 and 1000 °C anneal is correlated to the amount of fluorine remaining after anneal. (Read more)
- 798. Mater. Sci. Eng. C 25, 614-617 (2005) , “Incorporation of cobalt into ZnO nanoclusters”, Igor Ozerov, Françoise Chabre and Wladimir MarineThe structural, optical and magnetic properties of nanostructured ZnO films co-doped with cobalt and aluminium have been studied. The nanocrystalline films, with cluster sizes in range 50–100 nm, were deposited by pulsed laser ablation in a mixed atmosphere of oxygen and helium. The... (Read more)
- 799. Microelectron. Reliability 45, 71 (2005) , “A comprehensive model of PMOS NBTI degradation ”,Negative bias temperature instability has become an important reliability concern for ultra-scaled Silicon IC technology with significant implications for both analog and digital circuit design. In this paper, we construct a comprehensive model for NBTI phenomena within the framework of the standard reaction–diffusion model. We demonstrate how to solve the reaction–diffusion equations in a way that emphasizes the physical aspects of the degradation process and allows easy generalization of the existing work. We also augment this basic reaction–diffusion model by including the temperature and field-dependence of the NBTI phenomena so that reliability projections can be made under arbitrary circuit operating conditions. (Read more)
- 800. Microelectron. Reliability 45, 57 (2005) , “Characterization of interface defects related to negative-bias temperature instability SiON/Si<100> systems ”,Interface defects related to negative-bias temperature instability (NBTI) in an ultrathin plasma-nitrided SiON/ Si<100> system were characterized by using conductance–frequency measurements, electron-spin resonance measure- ments, and synchrotron radiation X-ray photoelectron spectroscopy. It was confirmed that NBTI is reduced by using D2-annealing instead of the usual H2-annealing. Interfacial Si dangling bonds (Pb1 and Pb0 centers) were detected in a sample subjected to negative-bias temperature stress (NBTS). Although we suggest that NBTS also generates non-Pb defects, it does not seem to generate nitrogen dangling bonds. These results show that NBTI of the plasma-nitrided SiON/Si system is predominantly due to Pb depassivation. Plasma nitridation was also found to increase the Pb1/Pb0 density ratio, modify the Pb1 defect structure, and increase the latent interface trap density by generating Si suboxides at the interface. These changes are likely to be the causes of NBTI in ultrathin plasma-nitrided SiON/Si systems. (Read more)
- 801. Nucl. Instrum. Methods Phys. Res. B 230, 220 (2005) , “Interaction between implanted fluorine atoms and point defects in preamorphized silicon”, G.Impellizzeri and J.H.R.dos Santos and S.Mirabella and E.Napolitani and A.Carnera and F.Priolo
- 802. Phys. Rev. B 72, 45204 (2005) , “Electron-positron momentum distributions associated with isolated silicon vacancies in 3C-SiC”, A. Kawasuso, M. Yoshikawa, H. Itoh, T. Chiba, T. Higuchi, K. Betsuyaku, F. Redmann, R. Krause-RehbergTwo-dimensional angular correlation of annihilation radiation (2D-ACAR) and coincidence Doppler broadening (CDB) of annihilation radiation measurements have been performed on electron-irradiated n-type 3C-SiC in which isolated silicon vacancies are responsible for positron trapping.... (Read more)
- 803. Phys. Rev. B 72, 245209 (2005) , “Formation of hydrogen-boron complexes in boron-doped silicon treated with a high concentration of hydrogen atoms”, N. Fukata, S. Fukuda, S. Sato, K. Ishioka, M. Kitajima, T. Hishita, and K. MurakamiThe formation of hydrogen (H) related complexes and their effect on boron (B) dopant were investigated in B-ion implanted and annealed silicon (Si) substrates treated with a high concentration of H. Isotope shifts by replacement of 10B with 11B were observed for some H-related... (Read more)
- 804. Phys. Rev. B 72, 235208 (2005) , “Spin multiplicity and charge state of a silicon vacancy (TV2a) in 4H-SiC determined by pulsed ENDOR”, N. Mizuochi, S. Yamasaki, H. Takizawa, N. Morishita, T. Ohshima, H. Itoh, T. Umeda, and J. IsoyaIn this paper, we unambiguously re-determine the spin multiplicity of TV2a by pulsed electron nucleus double resonance technique. The TV2a center is one of the most commonly observed defects in 4H-SiC, and its origin was... (Read more)
- 805. Phys. Rev. B 72, 235205 (2005) , “Passivation of copper in silicon by hydrogen”, C. D. Latham, M. Alatalo, R. M. Nieminen, R. Jones, S. Öberg, and P. R. BriddonThe structures and energies of model defects consisting of copper and hydrogen in silicon are calculated using the AIMPRO local-spin-density functional method. For isolated copper atoms, the lowest energy location is at the interstitial site with Td symmetry. Substitutional... (Read more)
- 806. Phys. Rev. B 72, 195211 (2005) , “Hydrogen local modes and shallow donors in ZnO”, G. Alvin Shi, Michael Stavola, S. J. Pearton, M. Thieme, E. V. Lavrov, and J. WeberThe annealing behavior of the free-carrier absorption, O-H vibrational absorption, and photoluminescence lines previously associated with H-related donors in ZnO has been studied. One set of H-related defects gives rise to O-H local vibrational mode absorption at either 3326 or 3611 ... (Read more)
- 807. Phys. Rev. B 72, 195207 (2005) , “Kinetics of divacancy annealing and divacancy-oxygen formation in oxygen-enriched high-purity silicon”, M. Mikelsen, E. V. Monakhov, G. Alfieri, B. S. Avset, and B. G. SvenssonIn this work the thermal kinetics of the transformation from the divacancy (V2) to the divacancy-oxygen (V2O) complex has been studied in detail, and activation energies, (Ea), have been obtained. Diffusion oxygenated float-zone silicon (DOFZ-Si)... (Read more)
- 808. Phys. Rev. B 72, 153201 (2005) , “Interstitial H2 in germanium by Raman scattering and ab initio calculations”, M. Hiller, E. V. Lavrov, J. Weber, B. Hourahine, R. Jones, and P. R. BriddonSingle-crystalline germanium wafers exposed to hydrogen and/or deuterium plasma are studied by means of Raman scattering. The Raman frequencies are compared to results of ab initio calculations. For samples treated with pure hydrogen, Raman measurements performed at a temperature of 80 K... (Read more)
- 809. Phys. Rev. B 72, 121201(R) (2005) , “*Cu0: A metastable configuration of the {Cus,Cui} pair in Si”, S. K. Estreicher, D. West, and M. SanatiFirst-principles theory shows that the substitutional-interstitial copper pair in Si (Si-CusCui) has a metastable state with Cui very near a tetrahedral interstitial site in a trigonal Cus-SiCui configuration... (Read more)
- 810. Phys. Rev. B 72, 115323 (2005) , “Defects in SiO2 as the possible origin of near interface traps in the SiC/SiO2 system: A systematic theoretical study”, J. M. Knaup, P. Deák, Th. Frauenheim, A. Gali, Z. Hajnal, and W. J. ChoykeA systematic study of the level positions of intrinsic and carbon defects in SiO2 is presented, based on density functional calculations with a hybrid functional in an α-quartz supercell. The results are analyzed from the point of view of the near interface traps (NIT), observed in... (Read more)
- 811. Phys. Rev. B 72, 115205 (2005) , “Defect identification in the AsGa family in GaAs”, H. Overhof and J.-M. SpaethAb initio total-energy calculations are presented for intrinsic defects in GaAs with a particular emphasis on hyperfine interactions in order to clarify the atomic structure of the various AsGa-related defects. For the AsGa-X2 defect complex the... (Read more)
- 812. Phys. Rev. B 72, 085213 (2005) , “First-principles study of the structure and stability of oxygen defects in zinc oxide”, Paul Erhart, Andreas Klein, and Karsten AlbeA comparative study on the structure and stability of oxygen defects in ZnO is presented. By means of first-principles calculations based on local density functional theory we investigate the oxygen vacancy and different interstitial configurations of oxygen in various charge states. Our results... (Read more)
- 813. Phys. Rev. B 72, 085212 (2005) , “Photoconductivity and infrared absorption study of hydrogen-related shallow donors in ZnO”, E. V. Lavrov, F. Börrnert, and J. WeberVapor phase grown ZnO samples treated with hydrogen and/or deuterium plasma were studied by means of photoconductivity and infrared (IR) absorption spectroscopy. Three bands at 180, 240, and 310 cm1 were observed in the photoconductivity spectra of hydrogenated ZnO. These are... (Read more)
- 814. Phys. Rev. B 72, 085208 (2005) , “Capacitance transient study of the metastable M center in n-type 4H-SiC”, H. Kortegaard Nielsen, A. Hallén, and B. G. SvenssonThe metastable M center in n-type 4H silicon carbide is studied in detail after it has been introduced by 2.5 MeV proton irradiation with a fluence of 1×1012 cm2. The experimental procedures included deep-level transient spectroscopy, carrier... (Read more)
- 815. Phys. Rev. B 72, 085206 (2005) , “Introduction and recovery of point defects in electron-irradiated ZnO”, F. Tuomisto, K. Saarinen, D. C. Look, and G. C. FarlowWe have used positron annihilation spectroscopy to study the introduction and recovery of point defects in electron-irradiated n-type ZnO. The irradiation (Eel=2 MeV, fluence 6×1017cm2) was performed at room temperature, and isochronal... (Read more)
- 816. Phys. Rev. B 72, 073205 (2005) , “Electronic behavior of rare-earth dopants in AlN: A density-functional study”, S. Petit, R. Jones, M. J. Shaw, P. R. Briddon, B. Hourahine, and T. FrauenheimLocal density functional calculations are carried out on Er, Eu, and Tm rare-earth (RE) dopants in hexagonal AlN. We find that the isolated impurities prefer to substitute for Al and, in contrast with isolated RE dopants in GaAs and GaN, REAl defects are electrically active and introduce... (Read more)
- 817. Phys. Rev. B 72, 045219 (2005) , “Fluorine in Si: Native-defect complexes and the supression of impurity diffusion”, Giorgia M. Lopez, Vincenzo Fiorentini, Giuliana Impellizzeri, Salvatore Mirabella, Enrico NapolitaniThe transient enhanced diffusion of acceptor impurities severely affects the realization of ultrahigh doping regions in miniaturized Si-based devices. Fluorine codoping has been found to suppress this transient diffusion, but the mechanism underlying this effect is not understood. It has been proposed that fluorine-impurity or fluorine–native-defect interactions may be responsible. Here we clarify this mechanism combining first-principles theoretical studies of fluorine in Si and purposely designed experiments on Si structures containing boron and fluorine. The central interaction mechanism is the preferential binding of fluorine to Si-vacancy dangling bonds and the consequent formation of vacancy-fluorine complexes. The latter effectively act as traps for the excess self-interstitials that would normally cause boron transient enhanced diffusion. Instead, fluorine-boron interactions are marginal and do not play any significant role. Our results are also consistent with other observations such as native-defect trapping and bubble formation. (Read more)
- 818. Phys. Rev. B 72, 035214 (2005) , “Vacancy-impurity complexes and limitations for implantation doping of diamond”, J. P. Goss, P. R. Briddon, M. J. Rayson, S. J. Sque, and R. JonesMany candidates have been proposed as shallow donors in diamond, but the small lattice constant means that many substitutional impurities generate large strains and thus yield low solubilities. Strained impurities favor complex formation with other defects and, in particular, the lattice vacancy. We... (Read more)
- 819. Phys. Rev. B 72, 035203 (2005) , “Optical detection of electron paramagnetic resonance for intrinsic defects produced in ZnO by 2.5-MeV electron irradiation in situ at 4.2 K”, L. S. Vlasenko and G. D. WatkinsIntrinsic defects produced in ZnO by 2.5-MeV electron irradiation in situ at 4.2 K are studied by optical detection of electron paramagnetic resonance (ODEPR). Observed in the photoluminescence (PL) are ODEPR signals, which are identified with the oxygen vacancy, VO+"... (Read more)
- 820. Phys. Rev. B 72, 033202 (2005) , “Electron-nuclear double-resonance study of Mn2+ ions in ZnGeP2 crystals”, N. Y. Garces, L. E. Halliburton, P. G. Schunemann, and S. D. SetzlerElectron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) have been used to characterize isolated Mn2+ (3d5) ions in a bulk ZnGeP2 crystal grown by the horizontal Bridgman technique. From the EPR data, we obtain... (Read more)
- 821. Phys. Rev. B 72, 014115 (2005) , “Lattice sites of implanted Fe in Si”, U. Wahl, J. G. Correia, E. Rita, J. P. Araújo, J. C. Soares, and The ISOLDE CollaborationThe angular distribution of β particles emitted by the radioactive isotope 59Fe was monitored following implantation into Si single crystals at fluences from 1.4×1012 cm2 to 1×1014 cm2. We... (Read more)
- 822. Phys. Rev. B 71, 245203 (2005) , “Electrical Activity of Er and Er-O Centers in Silicon”, D. Prezzi, T. A. G. Eberlein, R. Jones, J. S. Filhol, J. Coutindo, M. J. Shaw, P. R. Briddon.Spin-polarized density functional calculations are carried out on Er and Er-oxygen defects in crystalline Si. We find that the interstitial site is favored but the diffusion barrier of Eri is only 1.9 eV, and inevitably Eri forms complexes with impurities and... (Read more)
- 823. Phys. Rev. B 71, 241201(R) (2005) , “Ionization energies of phosphorus and nitrogen donors and aluminum acceptors in 4H silicon carbide from the donor-acceptor pair emission”, I. G. Ivanov, A. Henry, and E. JanzénThis paper deals with fitting the donor-acceptor pair luminescence due to P-Al pairs in 4H-SiC. It was possible to identify P at the Si cubic site as the shallower donor with ionization energy of 60.7 meV, as well as to distinguish the contribution in the spectrum from pairs involving this... (Read more)
- 824. Phys. Rev. B 71, 233201 (2005) , “Evidence for vacancy-interstitial pairs in Ib-type diamond”, Konstantin Iakoubovskii, Steen Dannefaer, and Andre StesmansDiamonds containing nitrogen in different forms have been irradiated by 3MeV electrons or 60Co gamma photons and characterized by optical absorption (OA) and electron spin resonance (ESR). An unusually low production rate of vacancies (V) and interstitials (I) was... (Read more)
- 825. Phys. Rev. B 71, 205212 (2005) , “Theoretical study of cation-related point defects in ZnGeP2”, Xiaoshu Jiang, M. S. Miao, and Walter R. L. LambrechtFirst-principles calculations are presented for the VZn and VGe cation vacancies and the ZnGe and GeZn antisites in ZnGeP2, using full-potential linearized muffin-tin orbital method supercell calculations in the local-density... (Read more)
- 826. Phys. Rev. B 71, 195201 (2005) , “Local modes of bond-centered hydrogen in Si:Ge and Ge:Si”, R. N. Pereira, B. Bech Nielsen, L. Dobaczewski, A. R. Peaker, and N. V. AbrosimovLocal vibrational modes of bond-centered hydrogen have been identified in Ge-doped Si (Si:Ge) and Si-doped Ge (Ge:Si) with in-situ-type infrared absorption spectroscopy. The infrared absorbance spectra recorded at 8 K immediately after implantation of the very dilute Si:Ge and Ge:Si alloys... (Read more)
- 827. Phys. Rev. B 71, 193204 (2005) , “Angular correlation of annihilation radiation associated with vacancy defects in electron-irradiated 6H-SiC”, A. Kawasuso, T. Chiba, T. HiguchiElectron-positron momentum distributions associated with vacancy defects in 6H-SiC after irradiation with 2-MeV electrons and annealing at 1000 °C have been studied using angular correlation of annihilation radiation measurements. It was confirmed that the above vacancy defects have... (Read more)
- 828. Phys. Rev. B 71, 193202 (2005) , “EPR and theoretical studies of negatively charged carbon vacancy in 4H-SiC”, T. Umeda, Y. Ishitsuka, J. Isoya, N. T. Son, E. Janzn, N. Morishita, T. Ohshima, H. Itoh, A. GaliCarbon vacancies (VC) are typical intrinsic defects in silicon carbides (SiC) and so far have been observed only in the form of positively charged states in p-type or semi-insulating SiC. Here, we present electron-paramagnetic-resonance (EPR) and photoinduced EPR (photo-EPR)... (Read more)
- 829. Phys. Rev. B 71, 174113 (2005) , “Atomistic mechanisms of amorphization during nanoindentation of SiC: A molecular dynamics study”, Izabela Szlufarska, Rajiv K. Kalia, Aiichiro Nakano, and Priya VashishtaAtomistic mechanisms underlying the nanoindentation-induced amorphization in SiC crystal has been studied by molecular dynamics simulations on parallel computers. The calculated load-displacement curve consists of a series of load drops, corresponding to plastic deformation, in addition to a... (Read more)
- 830. Phys. Rev. B 71, 165211 (2005) , “Theory of boron-vacancy complexes in silicon”, J. Adey, R. Jones, D. W. Palmer, P. R. Briddon, and S. ÖbergThe substitutional boron-vacancy BsV complex in silicon is investigated using the local density functional theory. These theoretical results give an explanation of the experimentally reported, well established metastability of the boron-related defect observed in p-type... (Read more)
- 831. Phys. Rev. B 71, 165210 (2005) , “Ion-implantation-induced extended defect formation in (0001) and (11-20) 4H-SiC”, J. Wong-leung, M. K. Linnarsson, B. G. Svensson, D. J. H. CockayneWe study the effect of substrate orientation namely (110) and (0001) oriented crystals on defect formation in 4H-SiC. The microstructure of the various samples, as-implanted with P and annealed, were studied by Rutherford backscattering spectrometry and channeling and transmission electron... (Read more)
- 832. Phys. Rev. B 71, 125210 (2005) , “Optical detection of electron paramagnetic resonance in room-temperature electron-irradiated ZnO”, L. S. Vlasenko and G. D. WatkinsThe dominant defect observed in the photoluminescence (PL) of room-temperature electron-irradiated ZnO by optical detection of electron paramagnetic resonance (ODEPR) is determined to be the positively charged oxygen vacancy (VO+" align="middle">). Its spectrum, labeled L3,... (Read more)
- 833. Phys. Rev. B 71, 125209 (2005) , “Properties of Ga-interstitial defects in AlxGa1–xNyP1–y”, N. Q. Thinh, I. P. Vorona, I. A. Buyanova, W. M. Chen, Sukit Limpijumnong, S. B. Zhang, Y. G. Hong, H. P. Xin, C. W. Tu, A. Utsumi, Y. Furukawa, S. Moon, A. Wakahara, and H. YonezuA detailed account of the experimental results from optically detected magnetic resonance (ODMR) studies of grown-in defects in (Al)GaNP alloys, prepared by molecular beam epitaxy, is presented. The experimental procedure and an in-depth analysis by a spin Hamiltonian lead to the identification of... (Read more)
- 834. Phys. Rev. B 71, 125202 (2005) , “Positively charged carbon vacancy in three inequivalent lattice sites of 6H-SiC: Combined EPR and density functional theory study”, V. Ya. Bratus', T. T. Petrenko, S. M. Okulov, and T. L. PetrenkoThe Ky1, Ky2, and Ky3 centers are the dominant defects produced in the electron-irradiated p-type 6H-SiC crystals. The electron paramagnetic resonance study of these defects has been performed in the temperature range of 4.2300 K at... (Read more)
- 835. Phys. Rev. B 71, 115213 (2005) , “Microvoid formation in hydrogen-implanted ZnO probed by a slow positron beam”, Z. Q. Chen, A. Kawasuso, Y. Xu, H. Naramoto, X. L. Yuan, T. Sekiguchi, R. Suzuki, and T. OhdairaZnO crystals were implanted with 2080 keV hydrogen ions up to a total dose of 4.4×1015 cm2. Positron lifetime and Doppler broadening of annihilation radiation measurements show introduction of zinc vacancy-related defects after implantation. These vacancies... (Read more)
- 836. Phys. Rev. B 71, 115205 (2005) , “Origin of the 6885-cm–1 luminescence lines in ZnO: Vanadium versus copper”, L. S. Vlasenko, G. D. Watkins, R. HelbigOptical detection of electron paramagnetic resonance reveals the I=7/2 EPR spectrum of V2+ in the sharp photoluminescence (PL) lines often observed at ~6885 cm1 in ZnO, which have universally been assumed previously to arise from copper. An alternative model for... (Read more)
- 837. Phys. Rev. B 71, 115204 (2005) , “Electron Spin Resonance Study of Paramagnetic Centers in Neutron-Irradiated Heat-Treated Silicon”, D. Pierreux and A. StesmansElectron spin resonance (ESR) was used to study neutron-induced defects in silicon as functions of anneal temperature Tan. For Tan below 200 °C, the ESR response is dominated by the Si-P3 and Si-P6 spectra, as observed before. At Tan=200 ... (Read more)
- 838. Phys. Rev. B 71, 075421 (2005) , “N-type electric conductivity of nitrogen-doped ultrananocrystalline diamond films”, Ying Dai, Dadi Dai, Cuixia Yan, Baibiao Huang, and Shenghao HanThe electronic structures of several possible nitrogen-related centers on the diamond surface and in the diamond grain-boundary have been studied using density functional theory approaches with cluster models. The results indicate that the nitrogen-vacancy related complex may be the shallow donor... (Read more)
- 839. Phys. Rev. B 71, 035213 (2005) , “Possibility for the electrical activation of the carbon antisite by hydrogen in SiC”, A. Gali, P. Deák, N. T. Son, and E. JanzénCalculations predict the carbon antisite to be the most abundant intrinsic defect in silicon carbide in a wide range of doping. The isolated carbon antisite is, however, optically and electronically inactive, therefore, difficult to observe by usual experimental techniques. However, CSi... (Read more)
- 840. Phys. Rev. B 71, 035205 (2005) , “Dominant hydrogen-oxygen complex in hydrothermally grown ZnO”, E. V. Lavrov, F. Börrnert, and J. WeberA hydrogen-related defect labeled as H-I*, observed in as-grown hydrothermal ZnO, is studied by means of infrared absorption spectroscopy. The defect possesses a stretch local vibrational mode at 3577.3 cm1 that is associated with a single hydrogen atom bound to oxygen with the O-H... (Read more)
- 841. Phys. Rev. Lett. 95, 225502 (2005) , “Evidence for Native-Defect Donors in n-Type ZnO”, D. C. Look, G. C. Farlow, Pakpoom Reunchan, Sukit Limpijumnong, S. B. Zhang, and K. NordlundRecent theory has found that native defects such as the O vacancy VO and Zn interstitial ZnI have high formation energies in n-type ZnO and, thus, are not important donors, especially in comparison to impurities such as H. In contrast, we use both theory... (Read more)
- 842. Phys. Rev. Lett. 95, 105502 (2005) , “Importance of Quantum Tunneling in Vacancy-Hydrogen Complexes in Diamond”, M. J. Shaw, P. R. Briddon, J. P. Goss, M. J. Rayson, A. Kerridge, A. H. Harker, and A. M. StonehamOur ab initio calculations of the hyperfine parameters for negatively charged vacancy-hydrogen and nitrogen-vacancy-hydrogen complexes in diamond compare static defect models and models which account for the quantum tunneling behavior of hydrogen. The static models give rise to hyperfine... (Read more)
- 843. Phys. Rev. Lett. 94, 186101 (2005) , “Geometric Characterization of a Singly Charged Oxygen Vacancy on a Single-Crystalline MgO(001) Film by Electron Paramagnetic Resonance Spectroscopy”, Martin Sterrer, Esther Fischbach, Thomas Risse, and Hans-Joachim FreundElectron paramagnetic resonance spectra of singly charged surface oxygen vacancies (F or color centers) formed by electron bombardment on a single-crystalline MgO film under UHV conditions are reported. The embedding of the defect in a well-defined geometrical environment allows not only for... (Read more)
- 844. Phys. Rev. Lett. 94, 165501 (2005) , “Vacancy-Impurity Complexes in Highly Sb-Doped Si Grown by Molecular Beam Epitaxy”, M. Rummukainen, I. Makkonen, V. Ranki, M. J. Puska, K. Saarinen, and H.-J. L. GossmannPositron annihilation measurements, supported by first-principles electron-structure calculations, identify vacancies and vacancy clusters decorated by 12 dopant impurities in highly Sb-doped Si. The concentration of vacancy defects increases with Sb doping and contributes significantly to the... (Read more)
- 845. Phys. Rev. Lett. 94, 125501 (2005) , “Delocalized Nature of the Edelta[prime]" align="middle"> Center in Amorphous Silicon Dioxide”, G. Buscarino, S. Agnello, and F. M. GelardiWe report an experimental study by electron paramagnetic resonance (EPR) of Edelta[prime]" align="middle"> point defect induced by γ-ray irradiation in amorphous SiO2. We obtained an estimation of the intensity of the 10 mT doublet characterizing the EPR... (Read more)
- 846. Phys. Rev. Lett. 94, 097602 (2005) , “Shallow Donors in Semiconductor Nanoparticles: Limit of the Effective Mass Approximation”, Serguei B. Orlinskii, Jan Schmidt, Edgar J. J. Groenen, Pavel G. Baranov, Celso de Mello Donegá, and Andries MeijerinkThe spatial distribution of the electronic wave function of a shallow, interstitial Li donor in a ZnO semiconductor nanocrystal has been determined in the regime of quantum confinement by using the nuclear spins as probes. Hyperfine interactions as monitored by electron nuclear double resonance... (Read more)
- 847. Proc. SPIE 6020, 60203D (2005) , “Effect of radio frequency bias on the optical and structural properties of nanocrystalline SiC films deposited by helicon wave plasma enhanced chemical vapor deposition”, Wei Yu, Chunsheng Wang, Wanbing Lu, Shuangkui Cui, Guangsheng FuNanocrystalline cubic silicon carbide thin films have been fabricated by helicon wave plasma enhanced chemical vapor deposition (HWP-CVD) on Si and Corning 7059 glass substrates using the mix plasma of SiH4, CH4, and H2. The effect of negative radio-frequency (rf) bias voltage on the optical and... (Read more)
- 848. Proc. SPIE 5732, 77 (2005) , “Growth of carbon nanotubes by sublimation of silicon carbide substrates”, William C. Mitchel, John Boeckl, David Tomlin, Weijie Lu, John Riqueur, Jonathan ReynoldsAligned carbon nanotubes (CNT"s) have been found to form on both the Si and C faces of silicon carbide (SiC) wafers at high temperature. The CNT"s form when the SiC wafer is exposed to temperatures in the range 1400-1700°C under moderate vacuum. The CNT"s are aligned roughly... (Read more)
- 849. Semiconductors 39, 709 (2005) , “Structural Defects and Electrical Conductivity in Nanocrystalline SiC:H Films Doped with Boron and Grown by Photostimulated Chemical-Vapor Deposition”, O. I. Shevaleevskiy, S. Y. Myong, K. S. Lim, S. Miyajima, M. KonagaiThe paramagnetic DB defects and dark conductivity σd in films of nanocrystalline hydrogenated silicon doped with boron and carbon (nc-SiC:H) and grown by photostimulated chemical vapor deposition are studied. It is shown that an increase in the doping level leads to a phase transition from the crystalline structure to an amorphous structure. The electrical conductivity increases as the doping level increases and attains the value of σd = 5.5 × 10-2 Ω-1 cm-1; however, the conductivity decreases once the phase transition has occurred. The concentration of DB defects decreases steadily as the doping level increases and varies from 1019 cm-3 (in the crystalline structure) to 9×1017 cm-3 (in the amorphous structure). (Read more)
- 850. Semiconductors 39, 493 (2005) , “Magnetic Ordering Effects in Heavily Doped GaAs:Fe Crystals”, B. P. Popov, V. K. Sobolevski?, E. G. Apushkinski?, V. P. Savel'evThe exchange coupling of Fe centers in GaAs crystals is studied by electron spin resonance (ESR). Transitions to a superparamagnetic state and to an impurity ferromagnetism domain are analyzed. A study of a system of single-domain magnetically ordered regions in GaAs:Fe with the transition to a ferromagnetic state occurring at the temperature T C1 = 460 K is described. It is shown that impurity ferromagnetism with a transition temperature T C2 of 60 K in a disordered system of Fe centers randomly distributed among superparamagnetic regions exists in GaAs:Fe. (Read more)
- 851. Spectrochim. Acta A. 61, 2595-2602 (2005) , “VO2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques”, P. Giri Prakash , J. Lakshmana RaoElectron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO–PbO–B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters... (Read more)
- 852. Superlatt. Microstruct. 38, 413-420 (2005) , “EPR study on magnetic Zn1−xMnxO”, Mariana Diaconu, Heidemarie Schmidt, Andreas Pppl, Rolf Bttcher, Joachim Hoentsch, Andreas Rahm, Holger Hochmuth, Michael Lorenz ,Marius GrundmannDiluted magnetic semiconductors (DMS), systems formed by replacing cations of the host semiconductor material with transition-metal ions, are developed for further use in spintronics. A good combination as a DMS is Zn1−xMnxO due to the ZnO wide band gap (3.37 eV) and the matching ionic... (Read more)
- 853. Appl. Phys. Lett. 85, 943-945 (2004) , “Paramagnetic defects of silicon nanowires”, A. Baumer, M. Stutzmann, and M. S. BrandtThe paramagnetic defects in and on Si nanowires (SiNWs) obtained by oxide-assisted growth were studied by conventional electron spin resonance spectroscopy. For the as-grown nanowires, three different defects were found: Dangling bonds or Pb-centers with g = 2.0065, located... (Read more)
- 854. Appl. Phys. Lett. 85, 926 (2004) , “Atomic cracks and (2×2×)-R30° reconstruction at 6H-SiC(0001) surface”, E. Amy, P. Soukiassian, C. BrylinskiWe investigate the Si-rich 3×3 to Si-terminated × phase transition of the 6H-SiC(0001) surface by atom-resolved scanning tunneling microscopy. We find a 2×2-R30° reconstruction, coexisting with few 3×3 domains. While a high-quality 3×3 surface preparation is... (Read more)
- 855. Appl. Phys. Lett. 85, 5209 (2004) , “Cross-sectional structure of carrot defects in 4H–SiC epilayers”, X. Zhang, S. Ha, M. Benamara, M. Skowronski, M. J. OLoughlin, J. J. SumakerisSurface morphology of carrot defects in 4HSiC epilayers is described based on optical microscopy and molten potassium hydroxide etching. Its crystallographic structure is investigated using cross-sectional transmission x-ray topography. A threading screw dislocation in substrate serves as the... (Read more)
- 856. Appl. Phys. Lett. 85, 4902-4904 (2004) , “Anomalous energetics and defect-assisted diffusion of Ga in silicon”, Claudio Melis, Giorgia M. Lopez, and Vincenzo FiorentiniWe study via first-principles calculations the energetics and diffusion of Ga in c-Si. In contrast to B and In, the favored Ga/self-interstitial complex is the tetrahedral interstitial GaT. Thus in the presence of self-interstitials Ga becomes interstitial, and is... (Read more)
- 857. Appl. Phys. Lett. 85, 4633-4635 (2004) , “Electrical and optical properties of rod-like defects in silicon”, J. P. Goss and P. R. BriddonSelf-interstitials in silicon can aggregate to form rod-like defects (RLDs) having both electrical and optical activity. We carry out local density functional calculations for both {113} and {111} RLDs to determine their structures and electrical activity. We find that small {113} RLDs are more... (Read more)
- 858. Appl. Phys. Lett. 85, 384-386 (2004) , “Nature of the acceptor responsible for p-type conduction in liquid encapsulated Czochralski-grown undoped gallium antimonide”, C. C. Ling, M. K. Lui, S. K. Ma, X. D. Chen, S. Fung, and C. D. BelingAcceptors in liquid encapsulated Czochralski-grown undoped gallium antimonide (GaSb) were studied by temperature dependent Hall measurement and positron lifetime spectroscopy (PLS). Because of its high concentration and low ionization energy, a level at EV + 34 meV is found... (Read more)
- 859. Appl. Phys. Lett. 85, 3780 (2004) , “Low temperature annealing of electron irradiation induced defects in 4H-SiC”, Antonio Castaldini, Anna Cavallini, Lorenzo Rigutti, Filippo NavaLow temperature annealing of electron irradiation-induced deep levels in 4H-SiC is reported. The major deep level transient spectroscopy peak S2 associated with the energy level at Ec0.39 eV disappears in the temperature range 360400 K, and some rearrangement... (Read more)
- 860. Appl. Phys. Lett. 85, 2827-2829 (2004) , “Formation of Ga interstitials in (Al,In)yGa1–yNxP1–x alloys and their role in carrier recombination”, N. Q. Thinh, I. P. Vorona, M. Izadifard, I. A. Buyanova, and W. M. ChenFormation of complex defects involving a Ga interstitial (Gai) in (Al,In)yGa1yNxP1x alloys and their effects on optical quality are studied by photoluminescence (PL) and optically detected magnetic... (Read more)
- 861. Appl. Phys. Lett. 85, 1716 (2004) , “Stability of deep centers in 4H-SiC epitaxial layers during thermal annealing”, Y. Negoro, T. Kimoto, and H. MatsunamiN-type epitaxial 4H-SiC layers grown by hot-wall chemical vapor deposition were investigated with regard to deep centers by capacitance-voltage measurements and deep level transient spectroscopy (DLTS). The DLTS spectra revealed that the concentrations of deep centers were reduced by one... (Read more)
- 862. Appl. Phys. Lett. 85, 1601 (2004) , “Different origins of visible luminescence in ZnO nanostructures fabricated by the chemical and evaporation methods”, D. Li, Y. H. Leung, A. B. Djurisic, Z. T. Liu, M. H. Xie, S. L. Shi, S. J. Xu, W. K. ChanWe prepared ZnO nanostructures using chemical and thermal evaporation methods. The properties of the fabricated nanostructures were studied using scanning electron microscopy, x-ray diffraction, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. It was found that the... (Read more)
- 863. Appl. Phys. Lett. 85, 1547 (2004) , “The effect of hydrogen etching on 6H-SiC studied by temperature-dependent current-voltage and atomic force microscopy”, S. Dogan, D. Johnstone, F. Yun, S. Sabuktagin, J. Leach, A. A. Baski, H. Morko, G. Li, B. Ganguly6HSiC was etched with hydrogen at temperatures between 1000 and 1450°C. The etched Si-terminated face for the 6H-SiC wafer was investigated by atomic force microscopy and temperature-dependent currentvoltage (IVT) measurements. Mechanical polishing... (Read more)
- 864. Appl. Phys. Lett. 85, 1538 (2004) , “Observation of fluorine-vacancy complexes in silicon”, P. J. Simpson, Z. Jenei, P. Asoka-Kumar, R. R. Robison, M. E. LawWe show direct evidence, obtained by positron annihilation spectroscopy, for the complexing of fluorine with vacancies in silicon. Both float zone and Czochralski silicon wafers were implanted with 30 keV fluorine ions to a fluence of 2×1014 ions/cm2, and studied in the... (Read more)
- 865. Appl. Phys. Lett. 84, 720-722 (2004) , “Isolated nickel impurities in diamond: A microscopic model for the electrically active centers”, R. Larico, L. V. C. Assali, and W. V. M. MachadoWe present a theoretical investigation on the structural and electronic properties of isolated nickel impurities in diamond. The atomic structures, symmetries, formation and transition energies, and hyperfine parameters of isolated interstitial and substitutional Ni were computed using ab... (Read more)
- 866. Appl. Phys. Lett. 84, 538 (2004) , “Interpretation of Fermi level pinning on 4H-SiC using synchrotron photoemission spectroscopy”, Sang Youn Han and Jong-Lam LeeThe Fermi level movements on 4H-SiC were observed in in situ deposited Ni contact using synchrotron radiation photoemission spectroscopy. For n-type SiC, the surface band bending increased about 0.75 eV with the Ni deposition, meaning the shift of Fermi level towards valence band edge.... (Read more)
- 867. Appl. Phys. Lett. 84, 4887-4889 (2004) , “Vacancy defects in O-doped GaN grown by molecular-beam epitaxy: The role of growth polarity and stoichiometry”, M. Rummukainen, J. Oila, A. Laakso, and K. SaarinenPositron annihilation spectroscopy is used to study vacancy defects in GaN grown by molecular-beam epitaxy due to different polar directions and varying stoichiometry conditions during oxygen doping. We show that Ga-polar material is free of compensating Ga vacancies up to [O] = 1018 ... (Read more)
- 868. Appl. Phys. Lett. 84, 4574-4576 (2004) , “Paramagnetic NO2 centers in thin γ-irradiated HfO2 layers on (100)Si revealed by electron spin resonance”, A. Stesmans and V. V. Afanas'evElectron spin resonance (ESR) analysis reveals the incorporation of N in (100)Si/HfO2 structures with ultrathin amorphous HfO2 films deposited by chemical vapor deposition (CVD) using Hf(NO3)4 as precursor, through detection, after 60Co... (Read more)
- 869. Appl. Phys. Lett. 84, 4514-4516 (2004) , “Doping-level-dependent optical properties of GaN:Mn”, O. Gelhausen, E. Malguth, and M. R. PhillipsThe optical properties of molecular-beam-epitaxy-grown GaN with different Mn-doping levels (523×1019 cm3) were studied by cathodoluminescence (CL) and optical transmission spectroscopy. Transmission measurements at 2 K revealed an absorption peak at... (Read more)
- 870. Appl. Phys. Lett. 84, 3909 (2004) , “Amorphization of silicon carbide by carbon displacement”, R. Devanathan, F. Gao, and W. J. WeberWe have used molecular dynamics simulations to examine the possibility of amorphizing silicon carbide (SiC) by exclusively displacing C atoms. At a defect generation corresponding to 0.2 displacements per atom, the enthalpy surpasses the level of melt-quenched SiC, the density decreases by about... (Read more)
- 871. Appl. Phys. Lett. 84, 3894-3896 (2004) , “H-related defect complexes in HfO2: A model for positive fixed charge defects”, Joongoo Kang, E.-C. Lee, and K. J. ChangBased on first-principles theoretical calculations, we investigate the hydrogenation effect on the defect properties of oxygen vacancies (VO) in HfO2. A defect complex of VO and H behaves as a shallow donor for a wide range of Fermi levels, with a... (Read more)
- 872. Appl. Phys. Lett. 84, 3876-3878 (2004) , “Observation of a Be-correlated donor state in GaN”, F. Albrecht, U. Reislöhner, G. Pasold, C. Hülsen, and W. WitthuhnA Be-related donor level was identified in the band gap of GaN. Thermal admittance spectroscopy (TAS) was combined with the radiotracer principle by applying the radioactive isotope 7Be which was implanted into n-type and p-type GaN. TAS spectra of n-type GaN... (Read more)
- 873. Appl. Phys. Lett. 84, 374-376 (2004) , “Impact of carbon on trap states in n-type GaN grown by metalorganic chemical vapor deposition”, A. Armstrong and A. R. ArehartThe effect of excess C incorporation on the deep level spectrum of n-type GaN grown by metalorganic chemical vapor deposition was investigated. Low-pressure (LP) growth conditions were used to intentionally incorporate excess C compared to atmospheric pressure (AP) growth conditions. GaN... (Read more)
- 874. Appl. Phys. Lett. 84, 3486-3488 (2004) , “Blueshift of yellow luminescence band in self-ion-implanted n-GaN nanowire”, S. Dhara, A. Datta, C. T. Wu, Z. H. Lan, K. H. Chen, and Y. L. WangOptical photoluminescence studies are performed in self-ion (Ga+)-implanted nominally doped n-GaN nanowires. A 50 keV Ga+ focused ion beam in the fluence range of 1×10142×1016 ions cm2 is used for the irradiation... (Read more)
- 875. Appl. Phys. Lett. 84, 3406-3408 (2004) , “Structure of 6H silicon carbide/silicon dioxide interface trapping defects”, David J. Meyer, Nathaniel A. Bohna, and Patrick M. LenahanWe utilize spin-dependent recombination (SDR) to observe deep level trap defects at or very near the interface of 6H silicon carbide and the SiO2 gate dielectric in SiC metal-oxide-semiconductor field effect transistors. The SDR response is strongly correlated to SiC/SiO2... (Read more)
- 876. Appl. Phys. Lett. 84, 3406 (2004) , “Structure of 6H silicon carbide/silicon dioxide interface trapping defects”, David J. Meyer, Nathaniel A. Bohna, Patrick M. Lenahan, Aivars J. LelisWe utilize spin-dependent recombination (SDR) to observe deep level trap defects at or very near the interface of 6H silicon carbide and the SiO2 gate dielectric in SiC metal-oxide-semiconductor field effect transistors. The SDR response is strongly correlated to SiC/SiO2... (Read more)
- 877. Appl. Phys. Lett. 84, 3064-3066 (2004) , “Comparison of the electrical activation of P+ and N+ ions co-implanted along with Si+ or C+ ions into 4H-SiC”, F. Schmid and G. PenslThe annealing behavior of P+ and N+ ions implanted into p-type 4H-SiC epilayers is studied by a temperature-dependent Hall-effect. Detailed investigations reveal that the electrical activation of implanted P+ ions is governed by the site competition effect,... (Read more)
- 878. Appl. Phys. Lett. 84, 3049-3051 (2004) , “Determination of the ionization energy of nitrogen acceptors in zinc oxide using photoluminescence spectroscopy”, Lijun Wang and N. C. GilesPhotoluminescence spectroscopy of nitrogen-related emissions in ZnO is used to establish the ionization energy of the substitutional nitrogen acceptor. The temperature dependence of the nitrogen-related electron-acceptor (e,A0) emission band has been monitored in as-grown... (Read more)
- 879. Appl. Phys. Lett. 84, 2841-2843 (2004) , “Structure and electrical activity of rare-earth dopants in GaN”, J.-S. Filhol and R. JonesDensity functional theory is used to investigate Eu, Er, and Tm rare earth (RE) impurities in GaN, paying particular attention to their structure, energetics, and electronic properties. The most stable site is when the RE is located at a Ga substitutional site but none of the defects possess deep... (Read more)
- 880. Appl. Phys. Lett. 84, 2760-2762 (2004) , “Activation mechanism of annealed Mg-doped GaN in air”, Yow-Jon LinIn this study, the activation mechanism of annealed Mg-doped GaN in air and the influence of ambient on activation of Mg-doped GaN were investigated. According to the experimental results, we found that the dissociation of MgGaH, and the formation of hydrogenated gallium vacancies... (Read more)
- 881. Appl. Phys. Lett. 84, 2635 (2004) , “Visible photoluminescence in ZnO tetrapod and multipod structures”, Aleksandra B. Djurisic, Yu Hang Leung, Wallace C. H. Choy, Kok Wai Cheah, Wai Kin ChanThe properties of ZnO tetrapod and multipod structures were investigated using scanning electron microscopy, x-ray diffraction, photoluminescence (PL), and electron paramagnetic resonance (EPR) spectroscopy. While there is relationship between g = 1.96 EPR and green PL in some of the samples,... (Read more)
- 882. Appl. Phys. Lett. 84, 2349-2351 (2004) , “Electrical characterization of phosphorus-doped n-type homoepitaxial diamond layers by Schottky barrier diodes”, Mariko Suzuki, Hiroaki Yoshida, Naoshi Sakuma, Tomio Ono, and Tadashi SakaiTemperature-dependent currentvoltage (IV), capacitancevoltage (CV) measurements, and frequency-dependent CV measurements have been carried out to investigate electrical properties of phosphorus (P)-doped n-type... (Read more)
- 883. Appl. Phys. Lett. 84, 2277-2279 (2004) , “Passivation of Mn acceptors in GaMnAs”, M. S. Brandt, S. T. B. Goennenwein, T. A. Wassner, F. Kohl, A. Lehner, H. Huebl, T. Graf, and M. StutzmannThe effects of hydrogen and deuterium on ferromagnetic GaAs doped with high concentrations of Mn (1021 cm3) are studied. Secondary ion mass spectroscopy depth profiles show that D is incorporated in the same concentration as Mn. The epilayers change from metallic to... (Read more)
- 884. Appl. Phys. Lett. 84, 2106-2108 (2004) , “Room-temperature silicon light-emitting diodes based on dislocation luminescence”, V. Kveder, M. Badylevich, E. Steinman, and A. IzotovWe demonstrate electroluminescence (EL) with an external efficiency of more than 0.1% at room temperature from glide dislocations in silicon. The key to this achievement is a considerable reduction of nonradiative carrier recombination at dislocations due to impurities and core defects by impurity... (Read more)
- 885. Appl. Phys. Lett. 84, 2055-2057 (2004) , “Evidence on the mechanism of boron deactivation in Ge-preamorphized ultrashallow junctions”, B. J. Pawlak and R. SurdeanuWe investigate the thermal stability of boron-doped junctions formed by Ge preamorphization and solid phase epitaxial regrowth. Isochronal annealing and characterization by sheet resistance, secondary-ion mass spectrometry, and spreading-resistance measurement are used to extract detailed... (Read more)
- 886. Appl. Phys. Lett. 84, 197-199 (2004) , “Narrow, deep level cathodoluminescence emission from semi-insulating GaAs”, J. K. RadhakrishnanCathodoluminescence investigations on bulk undoped semi-insulating GaAs samples taken from different sources reveal the presence of a deep level emission at 0.9 eV at 77 K, with a narrow full width at half maximum of 8 meV. The temperature-dependent and beam-parameter-dependent studies indicate... (Read more)
- 887. Appl. Phys. Lett. 84, 1895-1897 (2004) , “Mechanism of p-type-to-n-type conductivity conversion in boron-doped diamond”, Ying DaiWe report on the role of two boronhydrogen complexes in the conductivity conversion from p-type to n-type in boron-doped diamond samples. The calculated electronic structures of the simulated clusters show that the boronhydrogen complex of hydrogenboron pairs... (Read more)
- 888. Appl. Phys. Lett. 84, 1889-1891 (2004) , “"Umbrella"-like precipitates in nitrogen-doped Czochralski silicon wafers”, A. Kvit, A. Karoui, G. Duscher, and G. A. RozgonyiNitrogen effect on nucleation of oxygen precipitates in Czochralski Si has been investigated by transmission electron microscopy, Z-contrast imaging, and electron energy loss spectrometry (EELS). We have examined unusual "umbrella" shape oxygen precipitates in bulk of ingot in... (Read more)
- 889. Appl. Phys. Lett. 84, 1862-1864 (2004) , “Role of fluorine in suppressing boron transient enhanced diffusion in preamorphized Si”, G. Impellizzeri, J. H. R. dos Santos, S. Mirabella, and F. PrioloWe have explained the role of fluorine in the reduction of the self-interstitial population in a preamorphized Si layer under thermal treatment. For this purpose, we have employed a B spike layer grown by molecular-beam epitaxy as a marker for the self-interstitial local concentration. The... (Read more)
- 890. Appl. Phys. Lett. 84, 1859-1861 (2004) , “Nonradiative recombination centers in Ga(As,N) and their annealing behavior studied by Raman spectroscopy”, M. Ramsteiner, D. S. Jiang, J. S. Harris, and K. H. PloogNitrogen-related defects in diluted Ga(As,N) have been detected by Raman scattering in resonance with the localized E+ transition. These defects are attributed to local vibrational modes of nitrogen dimers on Ga- and As-lattice sites. Rapid thermal annealing under appropriate... (Read more)
- 891. Appl. Phys. Lett. 84, 1774 (2004) , “Reverse characteristics of pn diodes on 4H–SiC(000-1) C and (11-20) face”, Yasunori Tanaka, Kenji Fukuda, Kazuo Arai, Kazutoshi Kojima, Takaya Suzuki, Tsutomu YatsuoWe fabricated pn diodes on the 4HSiC(000-1) C and (11-20) face. The epitaxial growth of the n-type drift layer was carried out in chemical vapor deposition (CVD) reactor under the optimized conditions for each substrate. The pn junction was formed by... (Read more)
- 892. Appl. Phys. Lett. 84, 1713-1715 (2004) , “EL2-related metastable defects in semi-insulating GaAs”, D. KabirajThermally stimulated current spectroscopy, photoquenching, and photorecovery have been used to reveal the EL2-related metastable defect levels in semi-insulating GaAs. It has been found that one set of metastable levels is directly related to EL2 and the other set is indirectly related to EL2 defect... (Read more)
- 893. Appl. Phys. Lett. 84, 1704 (2004) , “Bistable defect in mega-electron-volt proton implanted 4H silicon carbide”, D. M. Martin, H. Kortegaard Nielsen, P. Lvque, A. Halln, G. Alfieri, B. G. SvenssonEpitaxial 4H-SiC n-type layers implanted at room temperature with a low fluence of mega-electron-volt protons have been measured by deep level transient spectroscopy (DLTS). The proton fluence of 1×1012 cm2 creates an estimated initial concentration of... (Read more)
- 894. Appl. Phys. Lett. 84, 1698-1700 (2004) , “Sensitivity of Pt/ZnO Schottky diode characteristics to hydrogen”, Suku Kim, B. S. Kang, and F. RenPt/ZnO Schottky diodes show changes in forward current of 0.3 mA at a forward bias of 0.5 V or alternatively a change of 50 mV bias at a fixed forward current of 8 mA when 5 ppm of H2 is introduced into a N2 ambient at 25 °C. The rectifying currentvoltage... (Read more)
- 895. Appl. Phys. Lett. 84, 1683-1685 (2004) , “Optically active erbium–oxygen complexes in GaAs”, J. CoutinhoDensity functional modeling of Er and ErO complexes in GaAs show that Er impurities at the Ga site are not efficient channels for exciton recombination, but decorative O atoms play crucial roles in inhibiting Er precipitation and in creating the necessary conditions for electron-hole capture.... (Read more)
- 896. Appl. Phys. Lett. 84, 1576-1578 (2004) , “Electron-beam-induced current observed for dislocations in diffused 4H-SiC P–N diodes”, S. Maximenko, S. Soloviev, D. Cherednichenko, and T. SudarshanThe electron-beam-induced current (EBIC) method was employed to investigate the electrical activity of dislocations in silicon carbide Schottky and diffused pn diodes. Dislocations in Schottky diodes appear as dark spots with the EBIC current signal at the dislocations reduced... (Read more)
- 897. Appl. Phys. Lett. 84, 1498 (2004) , “Effect of nitric oxide annealing on the interface trap density near the conduction bandedge of 4H–SiC at the oxide/(110) 4H–SiC interface”, S. Dhar, Y. W. Song, L. C. Feldman, T. Isaacs-Smith, C. C. Tin, J. R. Williams, G. Chung, T. Nishimura, D. Starodub, T. Gustafsson, E. GarfunkelNitric oxide postoxidation anneal results in a significant decrease of defect state density (Dit) near the conduction bandedge of n-4HSiC at the oxide/(110) 4HSiC interface. Comparison with measurements on the conventional (0001) Si-terminated face... (Read more)
- 898. Appl. Phys. Lett. 84, 1492-1494 (2004) , “Comparative study of defect energetics in HfO2 and SiO2”, W. L. Scopel, Antônio J. R. da Silva, W. Orellana, and A. FazzioWe perform ab initio calculations, based on density functional theory, for substitutional and vacancy defects in the monoclinic hafnium oxide (m-HfO2) and α-quartz (SiO2). The neutral oxygen vacancies and substitutional Si and Hf defects in HfO2... (Read more)
- 899. Eur. Phys. J. Appl. Phys. 27, 13-19 (2004) , “Measurement of process-induced defects in Si sub-micron devices by combination of EDMR and TEM”, T. Umeda, A. Toda, Y. MochizukiProcess-induced defects are a serious issue for modern sub-micron Si LSIs. To characterize such defects, two different techniques are useful: electrically detected magnetic resonance (EDMR) and transmission electron microscope (TEM), which can detect small (point) and extended defects, respectively. We applied EDMR and TEM to the issue of defect-induced leakage currents in dynamic-random-access memory (DRAM) cells. For our DRAM samples (a 0.25- μm-rule series), although TEM showed no extended defects, EDMR successfully detected two types of point defects: V2+O x (Si divacancy-oxygen complexes) and larger Si vacancies (at least larger than V6). We confirmed that these defects are the source of DRAM leakage currents. The observed defects were formed by ion implantation processes, but were more thermally stable than those in bulk Si crystals. The origins of this enhanced stability are attributed to the presence of oxygen atoms and a strong mechanical strain in LSIs. To clarify the origin of the complicated strain in LSI structures, we can directly measure the local-strain distribution in DRAM samples by means of convergent-beam electron diffraction (CBED) using TEM, which provides us with a valuable hint for understanding the formation mechanism of process-induced defects. (Read more)
- 900. IEEE Electron Device Lett. 25, 153 (2004) , “Evaluation of NBTI in HfO2 Gate-Dielectric Stacks With Tungsten Gates”,
- 901. J. Appl. Phys. 96, 747 (2004) , “Annealing of defect density and excess currents in Si-based tunnel diodes grown by low-temperature molecular-beam epitaxy”, Sung-Yong Chung, Niu Jin, Ryan E. Pavlovicz, and Paul R. BergerDeep-level transient spectroscopy (DLTS) measurements were performed in order to investigate the effects of post-growth heat treatment on deep level defects in Si layers grown by low-temperature molecular-beam epitaxy (LT-MBE) at 320 °C. In the LT-MBE as-grown samples, two dominant... (Read more)
- 902. J. Appl. Phys. 96, 6789 (2004) , “The role of N-related point defects in the degradation process of ZnSe-based white light-emitting diodes”, Koji KatayamaThe role of N-related point defects in the degradation process of ZnSe-based white light-emitting diodes under operation was investigated. The generation rate of microscopic dark spots, which do not correspond to the original stacking faults or threading dislocations in the epilayer, was found to... (Read more)
- 903. J. Appl. Phys. 96, 5613 (2004) , “Effects of high-temperature anneals on 4H–SiC Implanted with Al or Al and Si”, K. A. Jones, P. B. Shah, T. S. Zheleva, M. H. Ervin, M. A. Derenge, J. A. Freitas, S. Harmon, J. McGee, R. D. VisputeCo-implanting Si into 4HSiC with Al hinders the ability of the Al acceptors to activate electrically at the lower annealing temperatures, but for annealing temperatures > 1600 °C, the effect is much less, suggesting that the activation energy for incorporating Al as an acceptor no longer... (Read more)
- 904. J. Appl. Phys. 96, 5484 (2004) , “Defect levels and types of point defects in high-purity and vanadium-doped semi-insulating 4H–SiC”, M. E. Zvanut, V. V. Konovalov, Haiyan Wang, W. C. Mitchel, W. D. Mitchell, G. LandisElectron paramagnetic resonance (EPR) spectroscopy and photo-induced EPR are used to examine the point defects in vanadium-doped 4HSiC and high-purity semi-insulating (HPSI) 4HSiC grown by physical vapor transport. Both types of samples often exhibit a 1.1-eV activation energy,... (Read more)
- 905. J. Appl. Phys. 96, 530 (2004) , “Properties of arsenic antisite defects in Ga1–xMnxAs”, A. Wolos and M. KaminskaWe report the results of optical absorption measurements on Ga1xMnxAs layers grown by low-temperature molecular beam epitaxy. In the paramagnetic layers grown at very low temperatures (below 250 °C) the experiments reveal an absorption band at 1.2 eV... (Read more)
- 906. J. Appl. Phys. 96, 4960 (2004) , “Diffusion of boron in 6H and 4H SiC coimplanted with boron and nitrogen ions”, I. O. UsovThe diffusion behavior of boron (B) and nitrogen (N) implanted in 6H and 4H silicon carbide (SiC) samples was investigated using secondary ion mass spectroscopy. The samples were either coimplanted with B and N ions or implanted with each element alone. The annealing was performed at 1700 °C... (Read more)
- 907. J. Appl. Phys. 96, 4909 (2004) , “Deep levels created by low energy electron irradiation in 4H-SiC”, L. Storasta, J. P. Bergman, E. Janzén, and A. HenryWith low energy electron irradiation in the 80250 keV range, we were able to create only those intrinsic defects related to the initial displacements of carbon atoms in the silicon carbide lattice. Radiation induced majority and minority carrier traps were analyzed using capacitance transient... (Read more)
- 908. J. Appl. Phys. 96, 4189 (2004) , “Electron spin resonance study of GaAs:Er,O grown by organometallic vapor phase epitaxy”, Makoto Yoshida, Kensaku Hiraka, Hitoshi Ohta, Yasufumi Fujiwara, Atsushi Koizumi, Yoshikazu TakedaElectron spin resonance (ESR) measurements of GaAs:Er,O grown by organometallic vapor phase epitaxy have been performed at 9.49 GHz from 4.5 to 13 K. Several anisotropic ESR signals (A, B, C, and D) are observed, which is consistent with the previous reports. We... (Read more)
- 909. J. Appl. Phys. 96, 3721 (2004) , “Fluorine-enhanced boron deffusion induced by fluorine postimplantation in silicon”, Taiji NodaIn this article, the postimplanted fluorine effect on boron transient-enhanced diffusion (TED) and dose loss during a 750°C annealing is shown. 19F implants at 2 keV, after 11B implant at an energy of 1 keV,3×1014/cm2, have been investigated in... (Read more)
- 910. J. Appl. Phys. 96, 3687 (2004) , “Onset of implant-related recombination in self-ion implanted and annealed crystalline silicon”, Daniel MacdonaldThe impact of residual recombination centers after low-energy self-implantation of crystalline silicon wafers and annealing at 900 °C has been determined by bulk carrier lifetime measurements as a function of implant dose. Doses below 1013 cm2 resulted in no... (Read more)
- 911. J. Appl. Phys. 96, 320 (2004) , “Passivation of double-positioning twin boundaries in CdTe”, Yanfa Yan, M. M. Al-Jassim, and K. M. JonesWe present density-functional total-energy calculations to investigate the passivation effects of impurity elements such as Br, Cl, S, O, H, and Na on double-positioning twin boundaries in CdTe. We find that Br, Cl, S, and O atoms present passivation effects on the boundaries with different degrees,... (Read more)
- 912. J. Appl. Phys. 96, 2878 (2004) , “Influence of crystal defects on the piezoresistive properties of 3C–SiC”, M. Eickhoff and M. StutzmannWe present a model for the quantitative assessment of the influence of crystal defects on the piezoresistive properties of n-type cubic silicon carbide. In an extended carrier trapping model, the strain dependent transport at potential barriers formed by electrons in defect states at internal... (Read more)
- 913. J. Appl. Phys. 96, 2406-2408 (2004) , “Annealing behavior of the carbon vacancy in electron-irradiated 4H-SiC”, Z. Zolnai, N. T. Son, C. Hallin, and E. JanzénElectron paramagnetic resonance (EPR) was used to study the annealing behavior of the positively charged carbon vacancy (EI5 center) in electron-irradiated 4H-SiC. At ~1000 °C the EPR signal of the defect starts decreasing gradually. Clear ligand hyperfine structure is still observed after... (Read more)
- 914. J. Appl. Phys. 96, 1563 (2004) , “Electrical properties of GaSe doped with Er”, Yu-Kuei Hsu and Chen-Shiung ChangMeasurements of the Hall effect and Er-related luminescence were made on Er-doped GaSe. Deep-level transient spectroscopy (DLTS) was also performed. Hall measurements show that hole concentrations of 0.2%, 0.5%, and 1% Er-doped GaSe samples are 1.5×10176×1017... (Read more)
- 915. J. Appl. Phys. 96, 1458 (2004) , “Self-diffusion in isotopically enriched silicon carbide and its correlation with dopant diffusion”, K. Rschenschmidt, H. Bracht, N. A. Stolwijk, M. Laube, G. Pensl, G. R. BrandesDiffusion of 13C and 30Si in silicon carbide was performed with isotopically enriched 4H-28Si12C/natSiC heterostructures which were grown by chemical vapor phase epitaxy. After diffusion annealing at temperatures between 2000°C and... (Read more)
- 916. J. Appl. Phys. 96, 1341 (2004) , “Assignment of deep levels causing yellow luminescence in GaN”, C. B. Soh, S. J. Chua, and H. F. LimThe deep levels in GaN associated with yellow luminescence transitions have been investigated using photoluminescence, Hall measurements, and deep level transient spectroscopy (DLTS). Hall measurements on Si-doped GaN show the presence of donor levels at ~18, ~35, and ~70 meV, which are respectively... (Read more)
- 917. J. Appl. Phys. 95, 913 (2004) , “Vacancy-type defects in electroplated Cu films probed by using a monoenergetic positron beam”, A. UedonoPositron annihilation was used to probe vacancy-type defects in electroplated Cu films. Doppler broadening spectra of the annihilation radiation for Cu films deposited on samples with a Ta(20 nm)/SiO2(100 nm)/Si structure were measured with a monoenergetic positron beam. For an... (Read more)
- 918. J. Appl. Phys. 95, 8469 (2004) , “Self-diffusion of 12C and 13C in intrinsic 4H–SiC”, M. K. Linnarsson and M. S. JansonSelf-diffusion of carbon (12C and 13C) in low-doped (intrinsic) 4HSiC has been studied using secondary ion mass spectrometry. A two layer 13C enriched structure with 13C/12C ratios of 0.01 and 0.1, respectively, have been prepared by... (Read more)
- 919. J. Appl. Phys. 95, 8092 (2004) , “Determination of functional center local environment in copper-modified Pb[Zr0.54Ti0.46]O3 ceramics”, Rüdiger-A. EichelFerroelectric copper(II)-modified polycrystalline Pb[Zr0.54Ti0.46]O3 ceramics with a dopant concentration of 0.25 mol % were investigated by means of electron paramagnetic resonance and hyperfine sublevel correlation spectroscopy. Special emphasis was put on the... (Read more)
- 920. J. Appl. Phys. 95, 69 (2004) , “Deep-level transient spectroscopy study on double implanted n+–p and p+–n 4H-SiC diodes”, Souvick Mitra and Mulpuri V. RaoPlanar n+p and p+n junction diodes, fabricated in 4H-SiC epitaxial layers using a double-implantation technology (a deep-range acceptor followed by a shallow-range donor implantation and vice versa), are characterized using capacitance... (Read more)
- 921. J. Appl. Phys. 95, 6092 (2004) , “Recovery of the carrier density in arsenic-doped silicon after high energy (2 MeV) Si+ implantation”, D. Nobili, S. Solmi, and M. FerriCarrier density and mobility measurements were performed on heavily arsenic-doped silicon-on-insulator specimens after 2 MeV implantation of Si+ ions. It is found that implantation induces a marked reduction of the electron density, which increases with the concentration of active dopant,... (Read more)
- 922. J. Appl. Phys. 95, 57 (2004) , “Vacancy-related defect distributions in 11B-, 14N-, and 27Al-implanted 4H–SiC: Role of channeling”, M. S. JansonThe defect distributions in 11B-, 14N-, and 27Al-implanted epitaxial 4HSiC are studied using monoenergetic positron beams. At least three types of defects are needed to account for the Doppler broadening annihilation spectra and two of the defects are... (Read more)
- 923. J. Appl. Phys. 95, 490 (2004) , “Surface-state origin for the blueshifted emission in anodically etched porous silicon carbide”, Tilghman L. Rittenhouse, Paul W. Bohn, Tim K. Hossain, Ilesanmi Adesida, James Lindesay, Alfred MarcusAnodic etching of SiC yields a highly monodisperse distribution of nanometer dimension porous structures which extend to a significant depth. Cathodoluminescence (CL) studies of the porous layers yield luminescence peaks in the UV region, above the band gap energy of bulk SiC. Higher etching current... (Read more)
- 924. J. Appl. Phys. 95, 4752 (2004) , “Electrically active defects induced by sputtering deposition on silicon: The role of hydrogen”, F. Volpi and A. R. PeakerWe present a study of the electrically active defects produced in p-type silicon crystals underneath a titanium layer deposited by sputtering to form a Schottky contact. The defects were investigated by Deep Level Transient Spectroscopy and free carrier profiles were determined by... (Read more)
- 925. J. Appl. Phys. 95, 4728 (2004) , “Electrically active defects in irradiated 4H-SiC”, M. L. David4H-SiC epilayers were irradiated with either protons or electrons and electrically active defects were studied by means of deep level transient spectroscopy. Motion of defects has been found to occur at temperature as low as 350400 K. Indeed, the application of an electric field has been found... (Read more)
- 926. J. Appl. Phys. 95, 4655 (2004) , “Hydrogen behavior in SiO2 with high density of defects and locally concentrated silicon”, M. Ikeda, M. Nakagawa, R. Mitsusue, S. Kondo, and N. ImanishiUsing ion implantation techniques, we have studied the trapping, detrapping, and diffusion of H in SiO2 containing a high density of defects and a high concentration of excess Si. In SiO2 sample implanted with Si and H, the implanted H moves toward the surface after stopping at... (Read more)
- 927. J. Appl. Phys. 95, 4096 (2004) , “Nitridation effects on Pb center structures at SiO2/Si(100) interfaces ”,Interfacial defect structures of NO-nitride oxide on Si(100) were characterized by electron spin resonance spectroscopy. We confirmed that the effective g values of the Pb1 center are affected by interfacial nitridation even at a small nitrogen concentration of 5 at. %, while those of the Pb0 center proved to be unchanged. We observed that the shifted Pb1 line appeared gradually with interfacial nitrogen concentration, which suggests that the nitrogen-induced modified structure substitutes for the original Pb1 structure. Angular variations of the shifted Pb1 lines were also significantly different from those of pure oxide. Based on our analysis, we attributed the g value shift of the Pb1 center to dangling bond tilting, caused by the displacement of nearest-neighbor Si atoms. (Read more)
- 928. J. Appl. Phys. 95, 4012 (2004) , “Effects of implantation temperature on damage accumulation in Al-implanted 4H–SiC”, Y. Zhang, W. J. Weber, W. Jiang, C. M. Wang, V. Shutthanandan, A. HallnDamage accumulation in 4HSiC under 1.1 MeV Al22+" align="middle"> irradiation is investigated as a function of dose at temperatures from 150 to 450 K. Based on Rutherford backscattering spectroscopy and nuclear reaction analysis channeling spectra, the damage accumulation on... (Read more)
- 929. J. Appl. Phys. 95, 3404 (2004) , “Identification of vacancy–oxygen complexes in oxygen-implanted silicon probed with slow positrons”, M. Fujinami, T. Miyagoe, and T. SawadaDefects and their annealing behavior for low (2×1015/cm2) and high (1.7×1018/cm2) doses of 180 keV oxygen-implanted silicon have been investigated by the coincidence Doppler broadening (CDB) and lifetime measurements in variable-energy positron... (Read more)
- 930. J. Appl. Phys. 95, 3385 (2004) , “Optical investigations on the annealing behavior of gallium- and nitrogen-implanted ZnO”, F. ReussGallium and nitrogen ions have been implanted into ZnO crystals and metal organic vapor phase epitaxy grown ZnO layers. Postimplantation annealing behavior in the temperature range between 200 and 900 °C has been studied by means of Raman scattering and low-temperature photoluminescence. The... (Read more)
- 931. J. Appl. Phys. 95, 2532 (2004) , “Electrical resistivity of acceptor carbon in GaAs”, A. Ferreira da Silva and I. PepeThe electrical resistivity was investigated from room temperature down to 1.7 K for the shallow acceptor carbon in GaAs prepared by ion implantation with impurity concentrations between 1017 and 1019 cm3. Good agreement was obtained between the measured... (Read more)
- 932. J. Appl. Phys. 95, 1884-1887 (2004) , “Thermal activation of Mg-doped GaN as monitored by electron paramagnetic resonance spectroscopy”, M. E. Zvanut, D. M. Matlock, R. L. Henry, Daniel Koleske, Alma WickendenThe microscopic process involved with thermal activation of the Mg acceptors in GaN epitaxial films is investigated using electron paramagnetic resonance (EPR) spectroscopy. Samples were heat treated in dry N2 for 30 min at temperatures between 200 and 1000 °C. Below 850 °C, the... (Read more)
- 933. J. Cryst. Growth 264, 1-6 (2004) , “Ammonolysis of Ga2O3 and its application to the sublimation source for the growth of GaN film”, Y. J. Park , C. S. Oh , T. H. Yeom, Y. M. YuWe have observed the nagnetic resonance of conduction electrons in n-type indium antimonide, by the "heating" of the electron kinetic-energy temperature via the slsctron spins. This is the first direct evidence suggesting a contribution of spin-orbit coupling to relaxation in this system. In a steady-state spin-resonance experiment, a power PS=(M0=MZ)H/T1 is transferred to the systems(reservoirs) towards which the spins relax. Here, M0 is the equilibrium magnetization, MZ the component of the magnetization along the magnetic field H, and T1 the relaxation time. The reservoir of interest in our case is the kinetic energy of the eledtrons, and this is detected by an increase in the mobility μ. To our knowledge. this is the first observation of the power flow, due to relaxation, from the spins to a reservoir,applied to the ditection of magnetic resonance of conduction-electron spins. It differs in principle from usual spin-resonance observation methods, which are based on electromagnetic interactions of the spin system, such as the voltage induced in a resonator by the rotating magnetic moment, or again such as power absorption PS=MyHx from the rotating field Hx by the out-of- phase component My.Besides providing information on the relaxation mechanism, the present method (that we call "ralaxation" method) should also in some cases by much more sensitive than the usual "electromagnetic" detection methods. (Read more)
- 934. J. Phys. Chem. Solids 65, 639-645 (2004) , “Carbothermally-assisted aerosol synthesis of semiconducting materials in the system GaN/Mn”, Jerzy F. Janik , Mariusz Dryga , Cezary Czosnek , Maria Kamiska , Maria Palczewska and Robert T. PaineAerosol-assisted vapor phase synthesis aimed at preparation of magnetic semiconductor nanopowders of Ga1−xMnxN is carried out both from aqueous and methanol solution mixtures of gallium nitrate and manganese (II) nitrate. After an additional pyrolysis at 1000 °C under an ammonia flow,... (Read more)
- 935. J. Vac. Sci. Technol. B 22, 120-125 (2004) , “Properties of Fe-doped semi-insulating GaN structures”, A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, S. J. PeartonThe properties of semi-insulating GaN films with the lower part of the film doped with Fe are reported. The 300 K sheet resistivity of the films was 2×1010 /square with an activation energy of the dark conductivity of 0.5 eV. The Fermi level is also pinned at... (Read more)
- 936. Jpn. J. Appl. Phys. 43, 904 (2004) , “Characteristics of Irregular Forward Current Conduction in 4H-SiC pn Junction Diodes”, Takasumi Ohyanagi, Toshiyuki Ohno, Atsuo WatanabeSiC diodes show an irregular forward current conduction deviating from the standard diode theory, JF∝exp (VF), where JF is the forward current conduction density and VF is the forward voltage. However, it is not known... (Read more)
- 937. Jpn. J. Appl. Phys. 43, 1293 (2004) , “Reduction of Hollow Defects in 6H-SiC Single Crystals Grown by Sublimation Boule Growth Technique on (11\bar20) 6H-SiC Substrates”, Taro Nishiguchi, Yasuichi Masuda, Satoru Ohshima, Shigehiro NishinoSublimation boule growth of 6H-SiC on (11bar20) 6H-SiC substrates was investigated. Hollow defects were generated in the crystals grown on (11bar20) substrates, and they penetrated along the growth direction to the as-grown surface. A new growth model of SiC on (11bar20) SiC substrates that... (Read more)
- 938. Jpn. J. Appl. Phys. 43, 1076 (2004) , “Structure of an Oxygen-Related Defect Complex in SiC Studied with Electron Energy-Loss Spectroscopy”, Shunsuke Muto, Hiroshi Sugiyama, Tomohiko Kimura, Tetsuo TanabeThe atomic configuration of an oxygen-related defect complex in a SiC crystal was determined with the analyses of the extended energy-loss fine structure (EXELFS) and energy-loss near-edge structure (ELNES) in the electron energy-loss spectroscopy (EELS) associated with a transmission electron... (Read more)
- 939. Mater. Sci. Eng. A 375-377, 620-624 (2004) , “Evolution of the microstructure of disperse ZnO powders obtained by the freeze-drying method”, Z. V. Marinkovic, O. Milosevic, M. V. Nikolic, M. G. Kakazey, M. V. Karpec, T. V. Tomila , M. M. RisticFreeze-drying, as a cryochemical powder processing method is applied in the synthesis of ZnO submicrometer to nanosized powders. The process involves rapid freezing of the sprayed precursor solution, drying under vacuum by sublimation of the solvent and salt decomposition to oxide by thermal... (Read more)
- 940. Mater. Sci. Forum 457-460, 465 (2004) , “EPR and pulsed ENDOR study of EI6 and related defects in 4H-SiC”, T. Umeda, Y. Ishitsuka, J. Isoya, N. Morishita, T. Ohshima, T. Kamiya
- 941. Mater. Sci. Forum 457-460, 437 (2004) , “Defects in high-purity semi-insulating SiC”, N. T. Son, B. Magnusson, Z. Zolnai, A. Ellison, E. Janzn
- 942. Nature 430, 1009 (2004) , “Ultrahigh-quality silicon carbide single crystals”, Daisuke Nakamura, Itaru Gunjishima, Satoshi Yamaguchi, Tadashi Ito, Atsuto Okamoto, Hiroyuki Kondo, Shoichi Onda, Kazumasa TakatoriSilicon carbide (SiC) has a range of useful physical, mechanical and electronic properties that make it a promising material for next-generation electronic devices1,2. Careful consideration of the thermal conditions3-6 in which SiC {0001} is grown has resulted in improvements in crystal diameter and quality: the quantity of macroscopic defects such as hollow core dislocations (micropipes)7-9, inclusions, small-angle boundaries and longrange lattice warp has been reduced10,11. But some macroscopic defects (about 1–10 cm-2) and a large density of elementary dislocations (,104 cm-2), such as edge, basal plane and screw dislocations, remain within the crystal, and have so far prevented the realization of high-efficiency, reliable electronic devices in SiC (refs 12–16). Here we report a method, inspired by the dislocation structure of SiC grown perpendicular to the c-axis (a-face growth)17, to reduce the number of dislocations in SiC single crystals by two to three orders of magnitude, rendering them virtually dislocation-free. These substrates will promote the development of high-power SiC devices and reduce energy losses of the resulting electrical systems. (Read more)
- 943. Phys .Rev. Lett. 92, 178302 (2004) , “Nonvolatile Memory with Multilevel Switching: A Basic Model”, M. J. Rozenberg, I. H. Inoue, and M. J. SánchezThere is a current upsurge in research on nonvolatile two-terminal resistance random access memory (RRAM) for next generation electronic applications. The RRAM is composed of a simple sandwich of a semiconductor with two metal electrodes. We introduce here an initial model for RRAM with the... (Read more)
- 944. Phys. Rev. B 70, 245204 (2004) , “Silicon vacancy annealing and DI luminescence in 6H-SiC”, M. V. B. Pinheiro, E. Rauls, U. Gerstmann, S. Greulich-Weber, H. Overhof, and J.-M. SpaethCombining electron paramagnetic resonance measurements with ab initio calculations, we identify the VCCSi(SiCCSi) complex as a second annealing product of the silicon vacancy via an analysis of resolved carbon hyperfine interactions and of... (Read more)
- 945. Phys. Rev. B 70, 235212 (2004) , “EPR and theoretical studies of positively charged carbon vacancy in 4H-SiC”, T. Umeda, J. Isoya, N. Morishita, T. Ohshima, T. Kamiya, A. Gali, P. Dek, N. T. Son, E. JanznThe carbon vacancy is a dominant defect in 4H-SiC, and the "EI5" electron-paramagnetic-resonance (EPR) spectrum originates from positively charged carbon vacancies (VC+) at quasicubic sites. The observed state for EI5, however, has been attributed to a... (Read more)
- 946. Phys. Rev. B 70, 235211 (2004) , “Structure and vibrational spectra of carbon clusters in SiC”, Alexander Mattausch, Michel Bockstedte, and Oleg PankratovThe electronic, structural, and vibrational properties of small carbon interstitial and antisite clusters are investigated by ab initio methods in 3C- and 4H-SiC. The defects possess sizable dissociation energies and may be formed via condensation of carbon interstitials, e.g.,... (Read more)
- 947. Phys. Rev. B 70, 235208 (2004) , “Interstitial nitrogen and its complexes in diamond”, J. P. Goss, P. R. Briddon, S. Papagiannidis, and R. JonesNitrogen, a common impurity in diamond, can be displaced into an interstitial location by irradiation. The resultant interstitial defects are believed to be responsible for a range of infrared and electronic transitions that vary in thermal stability, and on the type of diamond. Of particular... (Read more)
- 948. Phys. Rev. B 70, 205214 (2004) , “Evidence of a sulfur-boron-hydrogen complex in GaAs grown by the liquid encapsulation Czochralski technique”, W. Ulrici and B. ClerjaudIn LEC-grown GaAs:S, two vibrational absorption lines are measured at 2382.2 and 2392.8 cm1 (T = 7 K) and assigned to 11B-H and 10B-H stretching modes. Uniaxial stress experiments reveal that the symmetry of the responsible complex is... (Read more)
- 949. Phys. Rev. B 70, 205211 (2004) , “Ni-vacancy defect in diamond detected by electron spin resonance”, K. IakoubovskiiTrigonal S = 1 NOL1/NIRIM5 center has been characterized by electron spin resonance (ESR) in nickel and boron doped diamond grown by the high-pressure high-temperature technique. Hyperfine interaction structure has been detected and attributed to six equivalent carbon sites and one Ni site.... (Read more)
- 950. Phys. Rev. B 70, 205209 (2004) , “Deep acceptor states of platinum and iridium in 4H-silicon carbide”, J. Grillenberger, U. Grossner, B. G. Svensson, F. Albrecht, W. Witthuhn, R. SielemannBand gap states of platinum and iridium in the hexagonal polytype 4H of silicon carbide are investigated by means of deep level transient spectroscopy (DLTS) in n- as well as p-type epitaxial layers. To establish a definite chemical assignment of band gap states to Pt and Ir the... (Read more)
- 951. Phys. Rev. B 70, 205207 (2004) , “Hydrogen-related photoluminescent centers in SiC”, D. Prezzi, T. A. G. Eberlein, R. Jones, B. Hourahine, P. R. Briddon, S. bergLocal density functional calculations are used to investigate models of the center responsible for a prominent set of luminescent lines with zero-phonon lines around 3.15 eV in hydrogen rich 4H-SiC and previously attributed to VSi-H. We find that the electronic structure of... (Read more)
- 952. Phys. Rev. B 70, 205203 (2004) , “Properties and formation mechanism of tetrainterstitial agglomerates in hydrogen-doped silicon”, Teimuraz Mchedlidze and Masashi SuesawaFor the tetrainterstitial agglomerate (I4), four additional silicon (Si) atoms are incorporated in an ordinary unit cell of Si lattice in such a manner that all atoms are four-coordinated and angles between bonds are not disturbed significantly. Microstructure, electrical... (Read more)
- 953. Phys. Rev. B 70, 205201 (2004) , “Interaction of hydrogen with boron, phosphorus, and sulfur in diamond”, E. B. Lombardi, Alison Mainwood, and K. OsuchThe production of n-type doped diamond has proved very difficult. Phosphorus, and possibly sulfur, when in substitutional sites in the lattice, forms a donor which could be used in electronic devices. Boron, which is a relatively shallow acceptor, can be passivated by hydrogen, and it is... (Read more)
- 954. Phys. Rev. B 70, 201204(R) (2004) , “Annealing of vacancy-related defects in semi-insulating SiC”, U. Gerstmann, E. Rauls, and H. OverhofThe annealing of P6/P7 centers (VCCSi pairs) in the presence of carbon vacancies in high concentrations typical for semi-insulating (SI) silicon carbide (SiC) is studied theoretically. The calculated hyperfine parameters support the suggestion of a negatively... (Read more)
- 955. Phys. Rev. B 70, 195344 (2004) , “Ab initio study of structural and electronic properties of planar defects in Si and SiC”, C. Raffy, J. Furthmüller, J.-M. Wagner, and F. BechstedtWe present ab initio calculations for internal interfaces in Si and SiC. Density-functional calculations within the local-density approximation and the pseudopotential-plane-wave approach are performed to understand the effect of such two-dimensional defects on the electronic properties. We... (Read more)
- 956. Phys. Rev. B 70, 193207 (2004) , “Hyperfine interaction of the nitrogen donor in 4H-SiC”, N. T. Son, E. Janzn, J. Isoya, S. YamasakiShallow N donors in n-type 4H-SiC were studied by electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR). For the N donor at the cubic site (Nk) in 4H-SiC, the hyperfine (hf) constants of the interaction with the nearest-neighbor... (Read more)
- 957. Phys. Rev. B 70, 144111 (2004) , “Identification of Cr3+ centers in Cs2NaAlF6 and Cs2NaGaF6 crystals by EPR and ENDOR paramagnetic resonance techniques”, H. Vrielinck, F. Loncke, F. Callens, P. Matthys, and N. M. KhaidukovChromium-doped Cs2NaAlF6 and Cs2NaGaF6 crystals have been investigated by using the techniques of electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) at X-band (9.5 GHz) and Q-band (34 GHz) frequencies. In both... (Read more)
- 958. Phys. Rev. B 70, 121201(R) (2004) , “Identification of Ga-interstitial defects in GaNyP1–y and AlxGa1–xNyP1–y”, N. Q. Thinh, I. P. Vorona, I. A. Buyanova, W. M. Chen, Sukit Limpijumnong, S. B. Zhang, Y. G. Hong, C. W. Tu, A. Utsumi, Y. Furukawa, S. Moon, A. Wakahara, and H. YonezuTwo Ga-interstitial (Gai) defects are identified by optically detected magnetic resonance as common grown-in defects in molecular beam epitaxial GaNyP1y and... (Read more)
- 959. Phys. Rev. B 70, 115210 (2004) , “Possible p-type doping with group-I elements in ZnO”, Eun-Cheol Lee and K. J. ChangBased on first-principles calculations, we suggest a method for fabricating p-type ZnO with group-I elements such as Li and Na. With group-I dopants alone, substitutional acceptors are mostly self-compensated by interstitial donors. In ZnO codoped with H impurities, the formation of... (Read more)
- 960. Phys. Rev. B 70, 115206 (2004) , “Optically detected magnetic resonance of epitaxial nitrogen-doped ZnO”, G. N. Aliev, S. J. Bingham, D. Wolverson, J. J. Davies, H. Makino, H. J. Ko, and T. YaoOptically detected magnetic resonance (ODMR) experiments on epitaxial nitrogen-doped ZnO show spectra due to (i) a shallow donor with the full wurtzite symmetry, (ii) a previously unobserved spin-1/2 center of axial symmetry whose principal axis is tilted slightly away from the crystal c... (Read more)
- 961. Phys. Rev. B 70, 115203 (2004) , “Different roles of carbon and silicon interstitials in the interstitial-mediated boron diffusion in SiC”, Michel Bockstedte, Alexander Mattausch, and Oleg PankratovThe interstitial and vacancy mediated boron diffusion in silicon carbide is investigated with an ab initio method. The boron interstitials in p-type and n-type materials are found to be far more mobile than the boron-vacancy complexes. A kick-out mechanism and an interstitialcy... (Read more)
- 962. Phys. Rev. B 70, 085202 (2004) , “Reassignment of phosphorus-related donors in SiC”, E. Rauls, M. V. B. Pinheiro, S. Greulich-Weber, and U. GerstmannCombining efficient density-functional based tight-binding molecular dynamics with ab initio calculations, we show that despite higher formation energies the incorporation of phosphorus at the carbon sublattice is favored by kinetic effects during the annealing processes. Based on the... (Read more)
- 963. Phys. Rev. B 70, 035203 (2004) , “High-resolution local vibrational mode spectroscopy and electron paramagnetic resonance study of the oxygen-vacancy complex in irradiated germanium”, P. Vanmeerbeek, P. Clauws, H. Vrielinck, B. Pajot, L. Van Hoorebeke, and A. Nylandsted LarsenIt was recently discovered that in electron-irradiated germanium doped with oxygen a local vibrational mode occurs at 669 cm1 that could be ascribed to the negatively charged oxygen-vacancy complex (VO). In the 669 cm1 band and in another... (Read more)
- 964. Phys. Rev. B 70, 033204 (2004) , “Electron-spin phase relaxation of phosphorus donors in nuclear-spin-enriched silicon”, Eisuke Abe, Kohei M. Itoh, Junichi Isoya, and Satoshi YamasakiWe report a pulsed electron paramagnetic resonance study of the phase relaxation of electron spins bound to phosphorus donors in isotopically purified 29Si and natural abundance Si (natSi) single crystals measured at 8 K. The two-pulse echo decay curves for both samples show... (Read more)
- 965. Phys. Rev. B 70, 024105 (2004) , “X- and Q-band ENDOR study of the Fe+(II) center in chlorinated SrCl2:Fe crystals”, D. Ghica, S. V. Nistor, H. Vrielinck, F. Callens, and D. SchoemakerThe 001 axially symmetric Fe+(II) center observed in SrCl2:Fe2+ crystals has been studied by the electron nuclear double resonance (ENDOR) technique in the microwave X and Q bands. This center is produced only in crystals grown in chlorine atmosphere... (Read more)
- 966. Phys. Rev. B 69, 45208 (2004) , “Intrinsic defects in GaN. II. Electronically enhanced migration of interstitial Ga observed by optical detection of electron paramagnetic resonance”, P. Johannesen, A. Zakrzewski, L. S. Vlasenko, G. D. Watkins, Akira Usui, Haruo Sunakawa, Masashi MizutaOptical excitation at 1.7 K with 364-nm laser light produces partial annealing recovery of the damage produced in GaN by 2.5-MeV electron irradiation in situ at 4.2 K. Observed is a reduction in the irradiation-produced 0.95-eV photoluminescence (PL) band, recovery in the visible... (Read more)
- 967. Phys. Rev. B 69, 45207 (2004) , “Intrinsic defects in GaN. I. Ga sublattice defects observed by optical detection of electron paramagnetic resonance”, K. H. Chow, L. S. Vlasenko, P. Johannesen, C. Bozdog, G. D. Watkins, Akira Usui, Haruo Sunakawa, Chiaki Sasaoka, Masashi MizutaIrradiation of GaN by 2.5-MeV electrons in situ at 4.2 K produces a broad photoluminescence (PL) band centered at 0.95 eV. Optical detection of electron paramagnetic resonance (ODEPR) in the band reveals two very similar, but distinct, signals, L5 and L6, which we identify as interstitial... (Read more)
- 968. Phys. Rev. B 69, 245207 (2004) , “Donor level of bond-center hydrogen in germanium”, L. Dobaczewski, K. Bonde Nielsen, N. Zangenberg, B. Bech Nielsen, A. R. Peaker, and V. P. MarkevichWe apply Laplace deep-level transient spectroscopy (LDLTS) in situ after low-temperature proton implantation into crystalline n-type germanium and identify a deep metastable donor center. The activation energy of the donor emission is ~110 meV when extrapolated to zero electric field.... (Read more)
- 969. Phys. Rev. B 69, 245205 (2004) , “Atomistic study of intrinsic defect migration in 3C-SiC”, Fei Gao, William J. Weber, M. Posselt, and V. BelkoAtomic-scale computer simulations, both molecular dynamics (MD) and the nudged-elastic band methods, have been applied to investigate long-range migration of point defects in cubic SiC (3C-SiC) over the temperature range from 0.36Tm to 0.95Tm (melting... (Read more)
- 970. Phys. Rev. B 69, 235202 (2004) , “Ab initio study of the annealing of vacancies and interstitials in cubic SiC: Vacancy-interstitial recombination and aggregation of carbon interstitials”, Michel Bockstedte, Alexander Mattausch, and Oleg PankratovThe annealing kinetics of mobile intrinsic defects in cubic SiC is investigated by an ab initio method based on density-functional theory. The interstitial-vacancy recombination, the diffusion of vacancies, and interstitials to defect sinks (e.g., surfaces or dislocations) as well as the... (Read more)
- 971. Phys. Rev. B 69, 233202 (2004) , “Diffusion of hydrogen in perfect, p-type doped, and radiation-damaged 4H-SiC”, B. Aradi, P. Dek, A. Gali, N. T. Son, E. JanznThe diffusion of interstitial atomic hydrogen in 4H-SiC was investigated theoretically, using the local density approximation of density functional theory. We have found that the diffusion barrier in the perfect crystal is 0.6 eV. Comparing this value with the calculated zero point vibration... (Read more)
- 972. Phys. Rev. B 69, 224108 (2004) , “Mechanical properties and elastic constants due to damage accumulation and amorphization in SiC”, F. Gao and W. J. WeberDamage accumulation due to cascade overlap, which was simulated previously, has been used to study the changes in elastic constants and the bulk and elastic moduli as a function of dose in SiC. These mechanical properties generally decrease with increasing dose, and the rapid decrease at low-dose... (Read more)
- 973. Phys. Rev. B 69, 193202 (2004) , “Optical and electrical properties of vanadium and erbium in 4H-SiC”, D. Prezzi, T. A. G. Eberlein, J.-S. Filhol, R. Jones, M. J. Shaw, P. R. Briddon, and S. ÖbergLocal-density-functional calculations are carried out on vanadium and erbium centers in 4H-SiC. Particular attention is paid to their electrical and optical properties. We find that both V and Er lie at Si sites and can exist in three charge states with deep donor and acceptor levels. While... (Read more)
- 974. Phys. Rev. B 69, 165215 (2004) , “Boron-hydrogen complexes in diamond”, J. P. Goss, P. R. Briddon, S. J. Sque, and R. JonesBoron in diamond traps hydrogen forming passive Bs-H pairs. Boron trapping two deuterium atoms has been speculated as forming a shallow donor (0.230.34 eV below the conduction band). We present the results of first-principles calculations of boron complexes with 24... (Read more)
- 975. Phys. Rev. B 69, 165206 (2004) , “Structural and vibrational properties of {N,N} pairs and {N,H} complexes in Si”, J. L. McAfee, He Ren, and S. K. EstreicherFirst-principles molecular-dynamics simulations are used to predict the structures and binding energies of interstitial nitrogen Ni, substitutional nitrogen Ns, the Ni-self-interstitial complex, the {Ni,Ni}, {Ni,Ns} =... (Read more)
- 976. Phys. Rev. B 69, 155206 (2004) , “Structure, energetics, and extrinsic levels of small self-interstitial clusters in silicon”, Giorgia M. Lopez and Vincenzo FiorentiniNative defects in Si are of obvious importance in microelectronic device processing. Self-interstitials in particular are known to mediate, in many cases, anomalous impurity diffusion. Here we study the energetics and electronic structure of single, double, and triple self-interstitial clusters in... (Read more)
- 977. Phys. Rev. B 69, 153202 (2004) , “Divacancy annealing in Si: Influence of hydrogen”, E. V. Monakhov, A. Ulyashin, G. Alfieri, A. Yu. Kuznetsov, B. S. Avset, and B. G. SvenssonWe have performed comparative studies of divacancy (V2) annealing in hydrogenated and nonhydrogenated Si by deep level transient spectroscopy. It is shown that the nonhydrogenated samples demonstrate the formation of divacancy-oxygen (V2O) complex during annealing of... (Read more)
- 978. Phys. Rev. B 69, 125218 (2004) , “Structure and properties of vacancy-oxygen complexes in Si1–xGex alloys”, V. P. Markevich, A. R. Peaker, J. Coutinho, R. Jones, V. J. B. Torres, S. Öberg, P. R. Briddon, L. I. Murin, L. Dobaczewski, and N. V. AbrosimovThe electronic properties and structure of vacancy-oxygen (VO) complexes in Czochralski-grown Si1xGex crystals (0<x<0.06) have been studied by means of capacitance transient techniques and ab initio modeling. At least three configurations... (Read more)
- 979. Phys. Rev. B 69, 125217 (2004) , “Occupation site change of self-interstitials and group-III acceptors in Si crystals: Dopant dependence of the Watkins replacement efficiency”, Y. Tokuyama, M. Suezawa, N. Fukata, T. Taishi, and K. HoshikawaWe studied the dependence of the Watkins replacement efficiency on the species of group-III impurities from the measurement of the concentration of IH2, a complex of one self-interstitial (I) and two H atoms. If the IH2 concentration depends on species of... (Read more)
- 980. Phys. Rev. B 69, 125214 (2004) , “Spectroscopic evidence for a N-Ga vacancy defect in GaAs”, H. Ch. Alt, Y. V. Gomeniuk, and B. WiedemannA local vibrational mode occurring at 638 cm1 in nitrogen-rich GaAs bulk crystals and 14N-implanted GaAs layers has been investigated by high-resolution Fourier transform infrared absorption spectroscopy. Measurements on samples coimplanted with 14N and... (Read more)
- 981. Phys. Rev. B 69, 125210 (2004) , “Dissociation of H-related defect complexes in Mg-doped GaN”, O. Gelhausen, M. R. Phillips, E. M. Goldys, T. Paskova, B. Monemar, M. Strassburg, and A. HoffmannPost-growth annealing and electron beam irradiation during cathodoluminescence were used to determine the chemical origin of the main optical emission lines in moderately and heavily Mg-doped GaN. The 3.27 eV donor-acceptor pair (DAP) emission line that dominates the emission spectrum in moderately... (Read more)
- 982. Phys. Rev. B 69, 125203 (2004) , “First-principles studies of the diffusion of B impurities and vacancies in SiC”, R. Rurali, E. Hernández, P. Godignon, J. Rebollo, and P. OrdejónIn this paper we analyze, by means of first-principles electronic structure calculations, the structural, energetic, and diffusive properties of B impurities in SiC as well as of vacancies. We focus our study on (i) determining the equilibrium structures of the impurity in the lattice by means of... (Read more)
- 983. Phys. Rev. B 69, 121201(R) (2004) , “EPR identification of two types of carbon vacancies in 4H-SiC”, T. Umeda, J. Isoya, N. Morishita, T. Ohshima, and T. KamiyaThe EI5 and EI6 centers are typical intrinsic defects in radiation-damaged and semi-insulating 4H-SiC. So far, their origins have been assigned to positively charged carbon vacancies (VC+) and silicon antisites (SiC+), respectively. However,... (Read more)
- 984. Phys. Rev. B 69, 115212 (2004) , “Defects produced in ZnO by 2.5-MeV electron irradiation at 4.2 K: Study by optical detection of electron paramagnetic resonance”, Yu. V. Gorelkinskii and G. D. WatkinsThe effect of 2.5 MeV electron irradiation in situ at 4.2 K on the properties of single crystalline ZnO is studied by photoluminescence (PL) and optically detected electron paramagnetic resonance (ODEPR). A new PL band is produced by the irradiation, and several annealing stages are observed... (Read more)
- 985. Phys. Rev. B 69, 115210 (2004) , “Optical and magnetic properties of Mn in bulk GaN”, A. Wolos, M. Palczewska, M. Zajac, J. Gosk, M. Kaminska, A. Twardowski, M. Bockowski, I. Grzegory, S. PorowskiWe report results of electron paramagnetic resonance, magnetization, and optical absorption studies of bulk GaN crystals doped with Mn and, for some samples, codoped with Mg acceptor. The experiments performed show that the charge state of the Mn ion in GaN depends on the Fermi level position in the... (Read more)
- 986. Phys. Rev. B 69, 115205 (2004) , “Formation of vacancy-impurity complexes by annealing elementary vacancies introduced by electron irradiation of As-, P-, and Sb-doped Si”, V. Ranki, A. Pelli, and K. SaarinenPositron annihilation experiments have been performed to identify defects created by annealing of electron irradiated of heavily As-, P-, and Sb-doped Si samples. We show that the vacancy-donor pairs (V-D1) migrate around 450 K, transforming into... (Read more)
- 987. Phys. Rev. B 69, 075210 (2004) , “Isoelectronic oxygen-related defect in CdTe crystals investigated using thermoelectric effect spectroscopy”, Salah A. Awadalla, Alan W. Hunt, Kelvin G. Lynn, Howard Glass, Csaba Szeles, and Su-Huai WeiAn oxygen-related defect was studied in nominally undoped CdTe crystals grown by the high pressure Bridgman technique using thermo-electrical effect spectroscopy and first-principles band structure calculations. Based on the linear relationship between the oxygen concentration and the emitted charge... (Read more)
- 988. Phys. Rev. B 69, 045322 (2004) , “Carbon antisite clusters in SiC: A possible pathway to the DII center”, Alexander Mattausch, Michel Bockstedte, and Oleg PankratovThe photoluminescence center DII is a persistent intrinsic defect which is common in all SiC polytypes. Its fingerprints are the characteristic phonon replicas in luminescence spectra. We perform ab initio calculations of vibrational spectra for various defect complexes and... (Read more)
- 989. Phys. Rev. B 69, 045208 (2004) , “Intrinsic defects in GaN. II. Electronically enhanced migration of interstitial Ga observed by optical detection of electron paramagnetic resonance”, P. Johannesen, A. Zakrzewski, L. S. Vlasenko, G. D. Watkins, Akira Usui, Haruo Sunakawa, and Masashi MizutaOptical excitation at 1.7 K with 364-nm laser light produces partial annealing recovery of the damage produced in GaN by 2.5-MeV electron irradiation in situ at 4.2 K. Observed is a reduction in the irradiation-produced 0.95-eV photoluminescence (PL) band, recovery in the visible... (Read more)
- 990. Phys. Rev. B 69, 045207 (2004) , “Intrinsic defects in GaN. I. Ga sublattice defects observed by optical detection of electron paramagnetic resonance”, K. H. Chow, L. S. Vlasenko, P. Johannesen, C. Bozdog, G. D. Watkins, Akira Usui, Haruo Sunakawa, Chiaki Sasaoka, and Masashi MizutaIrradiation of GaN by 2.5-MeV electrons in situ at 4.2 K produces a broad photoluminescence (PL) band centered at 0.95 eV. Optical detection of electron paramagnetic resonance (ODEPR) in the band reveals two very similar, but distinct, signals, L5 and L6, which we identify as interstitial... (Read more)
- 991. Phys. Rev. B 69, 045201 (2004) , “Hydrogenation of the dominant interstitial defect in irradiated boron-doped silicon”, N. Yarykin, O. V. Feklisova, and J. WeberThe H3-center with a level at Ev + 0.535 eV is observed in hydrogenated electron-irradiated boron-doped silicon. In samples with boron concentrations of (220)×1015 cm3 the center is the most abundant among all defects detected by... (Read more)
- 992. Phys. Rev. B 69, 035210 (2004) , “Evolution of voids in Al+-implanted ZnO probed by a slow positron beam”, Z. Q. Chen, M. Maekawa, S. Yamamoto, A. Kawasuso, X. L. Yuan, T. Sekiguchi, R. Suzuki, and T. OhdairaUndoped ZnO single crystals were implanted with aluminum ions up to a dose of 1015Al+/cm2. Vacancy defects in the implanted layers were detected using positron lifetime and Doppler broadening measurements with slow positron beams. It shows that vacancy clusters,... (Read more)
- 993. Phys. Rev. B 69, 035205 (2004) , “Metastable and nonmetastable recombination-induced defect reactions involving a hydrogen complex with a silicon vacancy in SiC”, Yaroslav KoshkaThe nontrivial recombination-induced behavior of the well-known low-temperature photoluminescence of the hydrogen complex with a silicon vacancy (VSi-H) has been previously reported by different authors. It was known to be limited to the metastable quenching and/or growth. In this... (Read more)
- 994. Phys. Rev. Lett. 93, 255502 (2004) , “Formation of Thermal Vacancies in Highly As and P Doped Si”, V. Ranki and K. SaarinenUsing positron annihilation measurements we observed the formation of thermal vacancies in highly As and P doped Si. The vacancies start to form at temperatures as low as 650 K and are mainly undecorated at high temperatures. Upon cooling the vacancies form stable vacancy-impurity complexes such as... (Read more)
- 995. Phys. Rev. Lett. 93, 245901 (2004) , “Ab Initio Calculations to Model Anomalous Fluorine Behavior”, Milan Diebel, Scott T. Dunhammplanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine behavior, we calculate the energy of fluorine defect structures in the framework of density functional theory. In addition to identifying the ground-state configuration and diffusion migration barrier of a single fluorine atom in silicon, a set of energetically favorable fluorine defect structures were found (FnVm). The decoration of vacancies and dangling silicon bonds by fluorine suggests that fluorine accumulates in vacancy-rich regions, which explains the fluorine redistribution behavior reported experimentally. (Read more)
- 996. Phys. Rev. Lett. 93, 086102 (2004) , “Reaction of the Oxygen Molecule at the Si(100)–SiO2 Interface During Silicon Oxidation”, Angelo Bongiorno and Alfredo PasquarelloUsing constrained ab initio molecular dynamics, we investigate the reaction of the O2 molecule at the Si(100)SiO2 interface during Si oxidation. The reaction proceeds sequentially through the incorporation of the O2 molecule in a Si-Si bond and the... (Read more)
- 997. Phys. Rev. Lett. 93, 055505 (2004) , “Ga Sublattice Defects in (Ga,Mn)As: Thermodynamical and Kinetic Trends”, F. Tuomisto, K. Pennanen, K. Saarinen, and J. SadowskiWe have used positron annihilation spectroscopy and infrared absorption measurements to study the Ga sublattice defects in epitaxial Ga1xMnxAs with Mn content varying from 0% to 5%. We show that the Ga vacancy concentration decreases and As antisite... (Read more)
- 998. Phys. Rev. Lett. 93, 055504 (2004) , “Degradation of Boron-Doped Czochralski-Grown Silicon Solar Cells”, J. Adey, R. Jones, D. W. Palmer, P. R. Briddon, and S. ÖbergThe formation mechanism and properties of the boron-oxygen center responsible for the degradation of Czochralski-grown Si(B) solar cells during operation is investigated using density functional calculations. We find that boron traps an oxygen dimer to form a bistable defect with a donor level in... (Read more)
- 999. Phys. Rev. Lett. 92, 47602 (2004) , “Overhauser Effect of 67Zn Nuclear Spins in ZnO via Cross Relaxation Induced by the Zero-Point Fluctuations of the Phonon Field”, Hubert Blok, Serguei B. Orlinski, Jan Schmidt, Pavel G. BaranovHole burning in and displacements of the magnetic-resonance absorption line of the electron spin of the shallow hydrogen-related donor in ZnO are observed upon resonant irradiation with microwaves at 275 GHz and at 4.5 K in a magnetic field of 10 T. These effects arise from an almost complete... (Read more)
- 1000. Phys. Rev. Lett. 92, 255504 (2004) , “Stable Fourfold Configurations for Small Vacancy Clusters in Silicon from ab initio Calculations”, D. V. Makhov and Laurent J. LewisUsing density-functional-theory calculations, we have identified new stable configurations for tri-, tetra-, and pentavacancies in silicon. These new configurations consist of combinations of a ring hexavacancy with three, two, or one interstitial atoms, respectively, such that all atoms remain... (Read more)
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