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- 1. phys. stat. sol. (b) 245, 1298-1314 (2008) , “EPR identification of intrinsic defects in SiC”, J. Isoya, T. Umeda, N. Mizuochi, N. T. Son, E. Janzen, T. OhshimaThe structure determination of intrinsic defects in 4H-SiC, 6H-SiC, and 3C-SiC by means of EPR is based on measuring the angular dependence of the 29Si/13C hyperfine (HF) satellite lines, from which spin densities, sp-hybrid ratio, and p-orbital direction can be determined over... (Read more)Si SiC diamond| EPR Theory electron-irradiation thermal-meas./anneal-exp.| +1 -1 0(neutral) 1.0eV~ 13C 29Si C1h C3v Carbon Csi D2d EI5/6 HEI1 HEI9/10 P6/7 Silicon T1 Td Tv2a V1/2/3 Vc Vsi antisite dangling-bond mono(=1) motional-effect n-type p-type pair(=2) quartet semi-insulating spin-relaxation triplet vacancy .inp files: SiC/Baranov/Baranov_g.inp SiC/EI5_C1h/5.inp SiC/EI5_C3v/5.inp SiC/EI6_RT/6.inp SiC/HEI10/HEI10a.inp SiC/HEI10/HEI10b.inp SiC/HEI1_C1h/1.inp SiC/HEI9/HEI9a.inp SiC/HEI9/HEI9b.inp SiC/SI5_C1h/4.inp SiC/Ky2/Ky2.inp SiC/Tv2a/Main.INP SiC/Vsi-_II_4H/Main.INP SiC/Vsi-_II_6H/Main.INP SiC/Vsi-_I_4H/Main.INP SiC/Vsi-_I_6H/Main.INP | last update: Takahide Umeda
- 2. Phys. Rev. B 75, 245202 (2007) , “Identification of positively charged carbon antisite-vacancy pairs in 4H-SiC”, T. Umeda, J. Ishoya, T. Ohshima, N. Morishita, H. Itoh, and A. GaliAn antisite-vacancy pair and a monovacancy are a set of fundamental stable and/or metastable defects in compound semiconductors. Theory predicted that carbon antisite-vacancy pairs would be much more stable in p-type SiC than silicon vacancies and that they would be a common defect. However,... (Read more)
- 3. Phys. Rev. B 75, 195335 (2007) , “Computational and experimental imaging of Mn defects on GaAs (110) cross-sectional surfaces”, A. Stroppa, X. Duan, M. Peressi, D. Furlanetto, and S. ModestiWe present a combined experimental and computational study of the (110) cross-sectional surface of Mn δ-doped GaAs samples. We focus our study on three different selected Mn defect configurations not previously studied in detail, namely surface interstitial Mn, isolated and in pairs, and... (Read more)
- 4. Phys. Rev. B 75, 195215 (2007) , “Effect of Co and O defects on the magnetism in Co-doped ZnO: Experiment and theory”, G. S. Chang, E. Z. Kurmaev, D. W. Boukhvalov, L. D. Finkelstein, S. Colis, T. M. Pedersen, A. Moewes, and A. DiniaThe electronic structure of Zn1−xCoxO (x=0.02, 0.06, and 0.10) diluted magnetic semiconductors is investigated using soft x-ray emission spectroscopy and first-principles calculations. X-ray absorption and emission measurements reveal that most Co... (Read more)
- 5. Phys. Rev. B 75, 195208 (2007) , “Supercell and cluster density functional calculations of the thermal stability of the divacancy in germanium”, C. Janke, R. Jones, S. Öberg, and P. R. BriddonLarge vacancy clusters, or voids, formed during crystal growth have been reported in Ge. The divacancy is a precursor to such clusters, and is believed to be stable up to 150 or 180 °C. It is also believed to form in Ge irradiated at room temperature where single vacancies are mobile. Density... (Read more)
- 6. Phys. Rev. B 75, 115418 (2007) , “Early stages of radiation damage in graphite and carbon nanostructures: A first-principles molecular dynamics study”, Oleg V. Yazyev, Ivano Tavernelli, Ursula Rothlisberger, and Lothar HelmUnderstanding radiation-induced defect formation in carbon materials is crucial for nuclear technology and for the manufacturing of nanostructures with desired properties. Using first-principles molecular dynamics, we perform a systematic study of the nonequilibrium processes of radiation damage in... (Read more)
- 7. Phys. Rev. B 75, 115206 (2007) , “Local-density-functional calculations of the vacancy-oxygen center in Ge”, A. Carvalho, R. Jones, J. Coutinho, V. J. B. Torres, S. Öberg, J. M. Campanera Alsina, M. Shaw, and P. R. BriddonWe carry out a comprehensive density-functional study of the vacancy-oxygen (VO) center in germanium using large H-terminated Ge clusters. The importance of a nonlinear core correction to account for the involvement of the 3d electrons in Ge-O bonds is discussed. We calculate the electrical... (Read more)
- 8. Phys. Rev. B 75, 085439 (2007) , “Real-space investigation of fast diffusion of hydrogen on Si(001) by a combination of nanosecond laser heating and STM”, C. H. Schwalb, M. Lawrenz, M. Dürr,, and U. HöferThe rearrangement of silicon dangling bonds induced by pulsed laser heating of monohydride-covered Si(001) surfaces has been studied by means of scanning tunneling microscopy (STM). The initial configurations, which were created by laser-induced thermal desorption, consist of isolated pairs of... (Read more)
- 9. Phys. Rev. B 75, 085204 (2007) , “Internal structure of the neutral donor-bound exciton complex in cubic zinc-blende and wurtzite semiconductors”, Bernard Gil, Pierre Bigenwald, Mathieu Leroux, Plamen P. Paskov, and Bo MonemarWe calculate the fine structure splitting of the near band edge donor-bound excitons in major cubic semiconductors using an approach inspired by an earlier one that consists in replacing the Morse potential by a Kratzer one, in order to account for the repulsion between the donor and the hole. A... (Read more)
- 10. Phys. Rev. B 75, 075312 (2007) , “Ferromagnetic to ferrimagnetic crossover in Cr-doped GaN nanohole arrays”, Q. Wang, Q. Sun, P. Jena, and Y. KawazoeUsing spin-polarized density-functional theory with exchange and correlation potential, approximated by both the generalized gradient approximation (GGA) and the GGA+U methods, we show that the coupling between a pair of Cr atoms substituted in GaN nanoholes is ferromagnetic. The interaction between... (Read more)
- 11. Phys. Rev. B 75, 075206 (2007) , “Isotope dependence of the vibrational lifetimes of light impurities in Si from first principles”, D. West and S. K. EstreicherThe vibrational lifetimes of a range of H-related defects and interstitial O (Oi) in Si, including isotopic substitutions, are calculated from first principles as a function of temperature. The theoretical approach is explained in detail. The vibrational lifetimes of... (Read more)
- 12. Phys. Rev. B 75, 075202 (2007) , “Theoretical study of Li and Na as n-type dopants for diamond”, J. P. Goss and P. R. BriddonPhosphorus is the n-type dopant of choice for diamond, but results in a deep donor level and alternatives are being sought. One possibility is the incorporation of interstitial alkali metal impurities such as Li and Na. We present the results of density-functional calculations used to predict... (Read more)
- 13. Phys. Rev. B 75, 073409 (2007) , “Why thermal H2 molecules adsorb on SiC(001)-c(4×2) and not on SiC(001)-(3×2) at room temperature”, Xiangyang Peng, Peter Krüger, and Johannes PollmannIn a recent experiment, Derycke et al. have made the exciting observation that H2 molecules readily adsorb dissociatively on the c(4×2) but not on the 3×2 surface of SiC(001) at room temperature. To unravel this spectacular reactivity difference, we have investigated a... (Read more)
- 14. Phys. Rev. B 75, 045211 (2007) , “Ab initio supercell calculations on aluminum-related defects in SiC”, A. Gali, T. Hornos, N. T. Son, E. Janzén, and W. J. ChoykeAb initio supercell calculations of the binding energies predict complex formation between aluminum and carbon interstitials in SiC. In high-energy implanted SiC aluminum acceptor can form very stable complexes with two carbon interstitials. We also show that carbon vacancy can be attached to... (Read more)
- 15. Phys. Rev. B 75, 033303 (2007) , “Excitons in silicon nanocrystallites: The nature of luminescence”, Eleonora Luppi, Federico Iori, Rita Magri, Olivia Pulci, Stefano Ossicini, Elena Degoli, and Valerio OlevanoThe absorption and emission spectra of silicon nanocrystals up to 1 nm diameter have been calculated within a first-principles framework. Our calculations include geometry optimization and the many-body effects induced by the creation of an electron-hole pair. Starting from hydrogenated silicon... (Read more)
- 16. Appl. Phys. Lett. 88, 253504 (2006) , “Single silicon vacancy-oxygen complex defect and variable retention time phenomenon in dynamic random access memories”, T. Umeda, K. Okonogi, K. Ohyu, S. Tsukada, K. Hamada, S. Fujieda, and Y. MochizukiThe variable retention time phenomenon has recently been highlighted as an important issue in dynamic random access memory (DRAM) technology. Based on electrically detected magnetic resonance and simulation studies, we suggest that a single Si vacancy-oxygen complex defect is responsible for this... (Read more)
- 17. Appl. Phys. Lett. 88, 182903 (2006) , “Effects of Al addition on the native defects in hafnia”, Q. Li, K. M. Koo, W. M. Lau, P. F. Lee, J. Y. Dai, Z. F. Hou, X. G. GongTwo occupied native defect bands are experimentally detected in pure HfO2. The density of states of band one in the middle of the band gap reduces drastically with the Al addition, while that of band two slightly above the valence-band maximum remains rather unaffected. We attribute the... (Read more)
- 18. Appl. Phys. Lett. 88, 162107 (2006) , “Physical origin of threshold voltage problems in polycrystalline silicon/HfO2 gate stacks”, Dae Yeon Kim, Joongoo Kang, and K. J. ChangBased on theoretical calculations, we find that at p+ polycrystalline silicon (poly-Si)/HfO2 gates, Si interstitials are easily migrated from the electrode, forming HfSi bonds with a charge transfer to the electrode, and the resulting interface dipole raises the Fermi level... (Read more)
- 19. Appl. Phys. Lett. 88, 153518 (2006) , “Negative bias temperature instability mechanism: The role of molecular hydrogen”, Anand T. Krishnan, Srinivasan Chakravarthi, Paul Nicollian, Vijay Reddy, and Srikanth KrishnanThe role of dimerization of atomic hydrogen to give molecular hydrogen in determining negative bias temperature instability (NBTI) kinetics is explored analytically. The time dependency of NBTI involving molecular hydrogen was found to obey a power law with a slope of 1/6, as opposed to the 1/4... (Read more)
- 20. Appl. Phys. Lett. 88, 091919 (2006) , “Calculation of deep carrier traps in a divacancy in germanium crystals”, J. Coutinho, V. J. B. Torres, R. Jones, A. Carvalho, S. berg, P. R. BriddonWe present an ab initio density functional study on the electronic structure and electrical properties of divacancies in Ge. Although suffering essentially different Jahn-Teller distortions when compared to the analogous defect in Si, the relative location of the electrical levels in the gap... (Read more)
- 21. 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)
- 22. 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)
- 23. 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)
- 24. 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)
- 25. 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)
- 26. 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)
- 27. 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)
- 28. 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)
- 29. 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)
- 30. 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)
- 31. 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)
- 32. 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)
- 33. Phys. Rev. Lett. 96, 55501 (2006) , “Divacancy in 4H-SiC”, N. T. Son, P. Carlsson, J. ul Hassan, E. Janz?n, 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)
- 34. 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
- 35. 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)
- 36. 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)
- 37. 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)
- 38. 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)
- 39. 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)
- 40. 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)
- 41. 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)
- 42. 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)
- 43. 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)
- 44. Phys. Rev. B 69, 233202 (2004) , “Diffusion of hydrogen in perfect, p-type doped, and radiation-damaged 4H-SiC”, B. Aradi, P. De?k, A. Gali, N. T. Son, E. Janz?nThe 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)
- 45. 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)
- 46. 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)
- 47. 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)
- 48. Phys. Rev. B 68, 205201 (2003) , “Ab initio study of the migration of intrinsic defects in 3C-SiC”, Michel Bockstedte, Alexander Mattausch, and Oleg PankratovThe diffusion of intrinsic defects in 3C-SiC is studied using an ab initio method based on density functional theory. The vacancies are shown to migrate on their own sublattice. The carbon split-interstitials and the two relevant silicon interstitials, namely the tetrahedrally... (Read more)
- 49. Phys. Rev. B 68, 155208 (2003) , “Theoretical study of vacancy diffusion and vacancy-assisted clustering of antisites in SiC”, E. Rauls, Th. Frauenheim, A. Gali, P. De?kUsing the self-consistent-charge density-functional-based tight-binding (SCC-DFTB) method, we have investigated the migration of vacancies at high temperatures, taking into account the entropy contribution to the Gibbs free energy. We have found that the energy barrier for sublattice migration of... (Read more)
- 50. Phys. Rev. B 68, 125201 (2003) , “Aggregation of carbon interstitials in silicon carbide: A theoretical study”, A. Gali, P. Deák, P. Ordejón, N. T. Son, E. Janzén, and W. J. ChoykeAb initio supercell calculations have been carried out to investigate clusters of carbon interstitials in 3C- and 4H-SiC. Based on the calculated formation energies, the complex formation of carbon interstitials or their aggregation to carbon antisites is energetically favored... (Read more)
- 51. Phys. Rev. B 68, 085202 (2003) , “Physics and chemistry of hydrogen in the vacancies of semiconductors”, Bernadett Szûcs, Adam Gali, Zoltán Hajnal, Peter Deák, and Chris G. Van de WalleHydrogen is well known to cause electrical passivation of lattice vacancies in semiconductors. This effect follows from the chemical passivation of the dangling bonds. Recently it was found that H in the carbon vacancy of SiC forms a three-center bond with two silicon neighbors in the vacancy, and... (Read more)
- 52. Phys. Rev. B 67, 205202 (2003) , “Formation and annealing of nitrogen-related complexes in SiC”, U. Gerstmann, E. Rauls, Th. Frauenheim, and H. OverhofWe propose a mechanism for the annealing of vacancy-related defects in SiC, based on ab initio total energy calculations. Our mechanism is based on the formation and migration of carbon and nitrogen split interstitials resulting in CSi(NC)n or... (Read more)
- 53. Phys. Rev. B 67, 155203 (2003) , “Correlation between the antisite pair and the DI center in SiC”, A. Gali, P. Deák, E. Rauls, N. T. Son, I. G. Ivanov, F. H. C. Carlsson, E. Janzén, and W. J. ChoykeThe DI low temperature photoluminescence center is a well-known defect stable up to 1700 °C annealing in SiC, still its structure is not yet known. Combining experimental and theoretical studies, in this paper we will show that the properties of an antisite pair can reproduce... (Read more)
- 54. Phys. Rev. Lett. 90, 225502 (2003) , “Z1/Z2 Defects in 4H–SiC”, T. A. G. Eberlein, R. Jones, P. R. BriddonFirst-principles calculations are carried out on models for the Z1/Z2 defects in 4HSiC which are found in as-grown and irradiated n-type material. We show that an interstitial-nitrogeninterstitial-carbon defect is exceptionally thermally stable,... (Read more)
- 55. Physica B 340-342, 15-24 (2003) , “Defects in SiC”, E. Janz?n, I. G. Ivanov, N. T. Son, B. Magnusson, Z. Zolnai, A. Henry, J. P. Bergman, L. Storasta, F. CarlssonRecent results from studies of shallow donors, pseudodonors, and deep level defects in SiC are presented. The selection rules for transitions between the electronic levels of shallow donors in 4H–SiC in the dipole approximation are derived and the ionization energy for the N donor at... (Read more)
- 56. Phys. Rev. B 65, 184108 (2002) , “Alphabet luminescence lines in 4H-SiC”, T. A. G. Eberlein, C. J. Fall, R. Jones, P. R. Briddon, S. ?bergFirst-principles density functional calculations are used to investigate antisite pairs in 4H-SiC. We show that they are likely to be formed in close proximity under ionizing conditions, and they possess a donor level and thermal stability consistent with the series of 40 photoluminescent lines... (Read more)
- 57. Phys. Rev. B 65, 085202 (2002) , “Divacancy in 3C- and 4H-SiC: An extremely stable defect”, L. Torpo, T. E. M. Staab, R. M. NieminenUsing first-principles calculations for divacancy defects in 3C- and 4H-SiC, we determine their formation energies and stability, their ionization levels, and relaxed geometries (symmetry point groups) for neutral as well as for charged states. For 4H-SiC all four possible nearest-neighbor divacancy... (Read more)
- 58. Phys. Rev. Lett. 88, 205502 (2002) , “Metastability of Amorphous Silicon from Silicon Network Rebonding”, R. Biswas, B. C. Pan, and Y. Y. YeWe propose a network rebonding model for light-induced metastability in amorphous silicon, involving bonding rearrangements of silicon and hydrogen atoms. Nonradiative recombination breaks weak silicon bonds and generates dangling bond?floating bond pairs, with very low activation energies. The... (Read more)
- 59. Phys. Rev. B 64, 245212 (2001) , “Structure of the silicon vacancy in 6H-SiC after annealing identified as the carbon vacancy-carbon antisite pair”, Th. Lingner, S. Greulich-Weber, J.-M. Spaeth, U. Gerstmann, E. Rauls, Z. Hajnal, Th. Frauenheim, H. OverhofWe investigated radiation-induced defects in neutron-irradiated and subsequently annealed 6H-silicon carbide (SiC) with electron paramagnetic resonance (EPR), the magnetic circular dichroism of the absorption (MCDA), and MCDA-detected EPR (MCDA-EPR). In samples annealed beyond the annealing... (Read more)
- 60. Phys. Rev. B 64, 245208 (2001) , “Ab initio and empirical-potential studies of defect properties in 3C-SiC”, Fei Gao, Eric J. Bylaska, William J. Weber, L. Ren? CorralesDensity functional theory (DFT) is used to study the formation and properties of native defects in 3C-SiC. Extensive calculations have been carried out to determine the formation of point defects and the stability of self-interstitials. Although there is good agreement in the formation of vacancies... (Read more)
- 61. Phys. Rev. B 63, 245202 (2001) , “Ab initio density-functional supercell calculations of hydrogen defects in cubic SiC”, B. Aradi, A. Gali, P. De?k, J. E. Lowther, N. T. Son, E. Janz?n, W. J. ChoykeBased on ab initio density-functional calculations in supercells of 3C-SiC, the stable configurations of hydrogen and dihydrogen defects have been established. The calculated formation energies are used to give semiquantitative estimates for the concentration of hydrogen in SiC after chemical vapor... (Read more)
- 62. J. Phys.: Condens. Matter 12, 3369 (2000) , “Local electronic structure around vacancies and vacancy-antisite complexes in ?-SiC”, G. Cubiotti, Yu. Kucherenko, A. Yaresko, A. Perlov, V. AntonovThe local electronic structure around vacancies and vacancy-antisite complexes in cubic SiC has been calculated by means of the LMTO (linear muffin-tin orbital) method and the supercell approach. In order to improve the description of the electronic structure near the energy gap, the... (Read more)
- 63. Phys. Rev. B 61, 12939 (2000) , “Dimer of Substitutional Carbon in Silicon Studied by EPR and ab initio Methods”, J. R. Byberg, B. Bech Nielsen, M. Fanciulli, S. K. Estreicher, P. A. Fedders.An EPR signal observed in carbon-doped float-zone silicon after irradiation with 2-MeV electrons at room temperature has been investigated. It represents a defect with S=1/2, an apparently isotropic g factor (=2.0030), and a complicated hyperfine structure from 29Si nuclei in five shells... (Read more)
- 64. Mater. Sci. Eng. B 61-62, 593 (1999) , “Electronic structure of the anti-structure pair in 3C–SiC”, L. Torpo and R. M. NieminenWe have studied the anti-structure pair (adjacent carbon CSi and silicon SiC antisites) in 3C–SiC using the plane–wave pseudopotential method. We report results for the formation energies, the ionization levels and the geometry of the relaxed structures of the defect in all its... (Read more)
- 65. Phys. Rev. Lett. 83, 372 (1999) , “Hydrogen Electrochemistry and Stress-Induced Leakage Current in Silica”, Peter E. Bl?chl and James H. StathisHydrogen-related defects in oxygen-deficient silica, representing the material of a thermal gate oxide, are analyzed using first-principles calculations. Energetics and charge-state levels of oxygen vacancies, hydrogen, and their complexes in the silica framework are mapped out. The neutral hydrogen... (Read more)
- 66. Phys. Rev. B 58, 9845 (1998) , “Theory of Carbon-Carbon Pairs in Silicon”, R. B. Capaz, A. Dal Pino, Jr., J. D. Joannopoulos.Interstitial-substitutional carbon pairs (CiCs) in silicon display interesting metastable behavior associated with two different structural configurations. In this work, we perform extensive ab initio calculations on this system. Our results show the following. (i) The... (Read more)
- 67. phys. stat. sol. (b) 210, 415-427 (1998) , “The Microscopic and Electronic Structure of Shallow Donors in SiC”, S. Greulich-WeberNitrogen donors in 6H-, 4H- and 3C-SiC were investigated using conventional electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) and the experimental results are discussed. An attempt is presented to interpret the experimentally found large differences in hyperfine... (Read more)
- 68. Phys. Rev. B 55, 2188-2194 (1997) , “Dynamic Properties of Interstitial Carbon and Carbon-Carbon Pair Defects in Silicon”, P. Leary, R. Jones, S. ?berg, V. J. B. Torres.Interstitial carbon, Ci, defects in Si exhibit a number of unexplained features. The Ci defect in the neutral charge state gives rise to two almost degenerate vibrational modes at 920 and 931 cm-1 whose 2:1 absorption intensity ratio naturally suggests a trigonal... (Read more)
- 69. Phys. Rev. B 47, 3620-3625 (1993) , “{H,B}, {H,C}, and {H,Si} pairs in silicon and germanium”, Dj. M. Maric, P. F. Meier, S. K. EstreicherThe interactions between interstitial H and substitutional B, C, and Si in crystalline silicon and germanium are studied in molecular clusters at the ab initio Hartree-Fock level with large basis sets. The energetics, electronic structures, and relative stabilities of these pairs are determined. Our... (Read more)
- 70. J. Appl. Phys. 54, 179-183 (1983) , “The Mechanism of the Enhancement of Divacancy Production by Oxygen During Electron Irradiation of Silicon. II. Computer Modeling”, G. S. Oehrlein, I. Krafcsik, J. L. Lindström, A. E. Jaworowski, and J. W. CorbettNumerical tests of possible models for the oxygen dependence of the divacancy introduction rate in silicon electron irradiated at room temperature were performed on a computer. Only the model in which oxygen traps Si self-interstitials can reproduce all the experimental data. Our modeling results... (Read more)
- 71. Sov. Phys. Solid State 23, 2126 (1981) , “Electron spin resonance of exchange-coupled vacancy pairs in hexagonal silicon carbide”, V. S. Va?ner, V. A. ll?in
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