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- 1. Phys. Rev. B 75, 085423 (2007) , “Room-temperature atmospheric oxidation of Si nanocrystals after HF etching”, X. D. Pi, L. Mangolini, S. A. Campbell, and U. KortshagenThe effect of HF etching of the silicon oxide shell covering the surface of Si nanocrystals (NCs) on the subsequent room-temperature atmospheric oxidation of Si-NCs has been investigated by means of photoluminescence measurements, Fourier transform infrared spectroscopy, and electron paramagnetic... (Read more)
- 2. J. Appl. Phys. 99, 113520 (2006) , “Effects of hydrogen bond redistribution on photoluminescence of a-SiC:H films under thermal treatment”, A. V. Vasin, S. P. Kolesnik, A. A. Konchits, V. I. Kushnirenko, V. S. Lysenko, A. N. Nazarov, A. V. Rusavsky, and S. AshokHydrogenated amorphous silicon carbide (a-SiC:H) films have been deposited using magnetron sputtering technique. An integrated investigation of the effect of vacuum annealing temperature on photoluminescence properties and paramagnetic defects and its correlation with structural... (Read more)
- 3. 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)
- 4. 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)
- 5. 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. JanzénContinuous-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)
- 6. 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. Syväjärvi, 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)
- 7. 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)
- 8. 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)
- 9. 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)
- 10. 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 Îź. 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)
- 11. Mater. Sci. Forum 457-460, 437 (2004) , “Defects in high-purity semi-insulating SiC”, N. T. Son, B. Magnusson, Z. Zolnai, A. Ellison, E. Janzén
- 12. 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)
- 13. 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)
- 14. 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)
- 15. J. Appl. Phys. 94, 519-524 (2003) , “Molecular nitrogen (N2-" align="middle">) acceptors and isolated nitrogen (N–) acceptors in ZnO crystals”, N. Y. Garces, Lijun Wang, N. C. Giles, L. E. Halliburton, G. Cantwell, D. B. EasonElectron paramagnetic resonance (EPR) has been used to investigate molecular nitrogen and isolated nitrogen acceptors in single crystals of ZnO. These samples were grown by the seeded chemical vapor transport method with N2 added to the gas stream. A five-line EPR spectrum is observed at... (Read more)
- 16. Physica B 340-342, 15-24 (2003) , “Defects in SiC”, E. Janzén, 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)
- 17. Appl. Phys. Lett. 81, 622 (2002) , “Role of copper in the green luminescence from ZnO crystals”, N. Y. Garces, L. Wang, L. Bai, N. C. Giles, L. E. Halliburton, G. CantwellElectron paramagnetic resonance (EPR), photoluminescence, and infrared optical absorption have been used to investigate a ZnO crystal before and after a thermal anneal for 1 h in air at 900 °C. The sample was an undoped high quality crystal grown by the chemical vapor transport method. In... (Read more)
- 18. Mater. Sci. Eng. 93, 39-48 (2002) , “Characterization of nitrides by electron paramagnetic resonance (EPR) and optically detected magnetic resonance (ODMR)”, E. R. Glaser, W. E. Carlos, G. C. B. Braga, J. A. Freitas, Jr , W. J. Moore, B. V. Shanabrook, A. E. Wickenden, D. D. Koleske, R. L. Henry, M. W. Bayerl, M. S. Brandt, H. Obloh, P. Kozodoy, S. P. DenBaars, U. K. Mishra, S. Nakamura, E. Haus, J. S. Speck, J. E. Van Nostrand, M. A. Sanchez, E. Calleja, A. J. Ptak, T. H. Myers and R. J. MolnarWe will highlight our recent work on the properties of residual defects and dopants in GaN heteroepitaxial layers and on the nature of recombination from InGaN single quantum well (SQW) light emitting diodes (LEDs) through magnetic resonance techniques. Electron paramagnetic resonance (EPR) and... (Read more)
- 19. Phys. Rev. B 65, 85312 (2002) , “Magnetic resonance studies of Mg-doped GaN epitaxial layers grown by organometallic chemical vapor deposition”, E. R. Glaser, W. E. Carlos, G. C. B. Braga, J. A. Freitas Jr, W. J. Moore, B. V. Shanabrook, R.L. Henry, A. E. Wickenden, D. D. Koleske, H.Obloh, P. Kozodoy, S. P. DenBaars, U. K. MishraElectron paramagnetic resonance (EPR) and optically detected magnetic resonance (ODMR) experiments have been performed on a set of GaN epitaxial layers doped with Mg from 2.5×1018 to 5.0×1019 cm-3. The samples were also characterized by secondary-ion-mass... (Read more)
- 20. Phys. Rev. B 65, 205202 (2002) , “Defects observed by optical detection of electron paramagnetic resonance in electron-irradiated p-type GaN”, L. S. Vlasenko, C. Bozdog, G. D. Watkins, F. Shahedipour, B. W. WesselsIrradiation of p-type (Mg-doped) GaN in situ at 4.2 K by 2.5 MeV electrons reduces the visible luminescence and creates a broad luminescence band in the infrared at ?0.95?eV. Upon annealing at 180 K, partial recovery of the visible luminescence occurs and a well resolved S=1 center is observed by... (Read more)
- 21. Phys. Rev. Lett. 89, 135507 (2002) , “Diffusion and Reactions of Hydrogen in F2-Laser-Irradiated SiO2 Glass”, Koichi Kajihara, Linards Skuja, Masahiro Hirano, and Hideo HosonoThe diffusion and reactions of hydrogenous species generated by single-pulsed F2 laser photolysis of SiO-H bond in SiO2 glass were studied in situ between 10 and 330Â K. Experimental evidence indicates that atomic hydrogen (H0) becomes mobile even at temperatures as... (Read more)
- 22. Mater. Sci. Eng. R 33, 135-207 (2001) , “Comprehensive characterization of hydride VPE grown GaN layers and templates”, H. MorkoçGaN community has recently recognized that it is imperative that the extended, and point defects in GaN and related materials, and the mechanisms for their formation are understood. This is a first and an important step, which must be followed by defect reduction before full implementation of this... (Read more)
- 23. Phys. Rev. B 64, 115308 (2001) , “Experimental Investigation of Band Structure Modification in Silicon Nanocrystals”, B. J. Pawlak, T. Gregorkiewicz, C. A. J. Ammerlaan, W. Takkenberg, F. D. Tichelaar, P. F. A. Alkemade.Experimental studies of size-related effects in silicon nanocrystals are reported. We present investigations carried out on nanocrystals prepared from single-crystal Si:P wafer by ball milling. The average final grain dimension varied depending on the way of preparation in the range between 70 and... (Read more)
- 24. Physica B 308-310, 691 (2001) , “Contactless studies of semi-insulating 4H–SiC”, W. E. Carlos, W. J. Moore, G. C. B Braga, J. A. Freitas, Jr. , E. R. Glaser and B. V. ShanabrookSemi-insulating (SI) silicon carbide is important for applications in high-power, high-frequency electronics, such as SiC MESFETs and GaN FETs. In this work, we discuss the use of low-temperature electron paramagnetic resonance (EPR), room- and low-temperature FTIR and photoluminescence as potential... (Read more)
- 25. Physica B 304, 12 (2001) , “Origin of yellow luminescence in n-GaN induced by high-energy 7 MeV electron irradiation”, Yasuhiko Hayashi, Tetsuo Soga, Masayoshi Umeno, Takashi JimboThe yellow luminescence band in high-energy 7 MeV electron-irradiated n-GaN is investigated as a function of electron irradiation dose. Both the yellow-band intensity and the near-bandedge photoluminescence (PL) intensity decrease continually with increasing electron irradiation dose. The decrease... (Read more)
- 26. phys. stat. sol. (b) 221, 625-631 (2000) , “Identification of the Gold-Lithium Defect L1 in Silicon with the Trigonal Centre Au2--(Li+)3 by Electrical, Optical and Magnetic Resonance Spectroscopy”, B. Langhanki, J. M. SpaethN-type silicon doped with gold and lithium was investigated by Electron Paramagnetic Resonance (EPR) and Deep Level Transient Spectroscopy (DLTS), using two sets of samples with different defect concentrations of both gold and lithium. Photoluminescence (PL) on both sets of samples allowed to... (Read more)
- 27. J. Non-Cryst. Solids 241, 71-73 (1998) , “Long luminescent glass: Tb3+-activated ZnO–B2O–SiO2 glass”, Masaaki Yamazaki, Yoshinori Yamamoto, Shinobu Nagahama, Naruhito Sawanobori, Masafumi Mizuguchi , Hideo HosonoIt has been found that zinc borosilicate glasses 60ZnO–20B2O3–20SiO2 doped with 0.2 mol% Tb2O3 exhibit phosphorescence after exciting with 254 nm light. This phosphorescence arises from f–f transitions of Tb3+ ions and is observable by the eye, in the dark for up to 1 h after... (Read more)
- 28. J. Non-Cryst. Solids 239, 16-48 (1998) , “Optically active oxygen-deficiency-related centers in amorphous silicon dioxide”, Linards SkujaThe spectroscopic properties, structure and interconversions of optically active oxygen-deficiency-related point defects in vitreous silica are reviewed. These defects, the E′-centers (oxygen vacancies with a trapped hole or 3-fold-coordinated silicons), different variants of diamagnetic... (Read more)GeO2 SiO2| EPR PL gamma-irradiation optical-spectroscopy| 0.5-1.0eV 1.0eV~ 1H 2.0eV~ 3.0eV~ 4.0eV~ 5.0eV~(larger) Chlorine E' E'-alpha E'-betha E'-delta E'-gamma Germanium H(I) H(II) Hydrogen ODC ODC(I) ODC(II) OHC Oxygen POR Silicon amorphous dangling-bond dielectric interstitial pair(=2) surface triplet vacancy | last update: Takahide Umeda
- 29. Nucl. Instrum. Methods Phys. Res. B 141, 566-574 (1998) , “Defect formation in amorphous SiO2 by ion implantation: Electronic excitation effects and chemical effects”, H. Hosono, N. MatsunamiIntrinsic defect formation in amorphous (a-) SiO2 by ion implantation was examined with emphasis upon electronic excitation effects and chemical reaction effects. 10 MeV proton beam and boron beam irradiated silica platelets to examine electronic excitation effects and chemical reaction effects. In... (Read more)
- 30. Phys. Rev. Lett. 80, 317-320 (1998) , “Experimental Evidence for Frenkel Defect Formation in Amorphous SiO2 by Electronic Excitation”, H. Hosono, H. Kawazoe, N. MatsunamiConcentrations of defects in amorphous SiO2 created by implantation of 10 MeV protons were examined. The depth profile of Si-Si bonds, E? centers, or peroxy radicals (PORs) was close to that of electronic energy loss. Interstitial O2 molecules were identified and... (Read more)
- 31. phys. stat. sol. (a) 162, 95-151 (1997) , “EPR and ENDOR Investigations of Shallow Impurities in SiC Polytypes”, S. Greulich-WeberInvestigations of nitrogen donors in 6H-, 4H- and 3C-SiC using conventional electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and optical detection of EPR and ENDOR as well as optical absorption and emission spectroscopy are reviewed and critically discussed. An... (Read more)
- 32. Appl. Phys. Lett. 68, 403 (1996) , “Correlation between photoluminescence and oxygen vacancies in ZnO phosphors”, K. Vanheusden, C. H. Seager, W. L. Warren, D. R. Tallant, and J. A. VoigtBy combining electron paramagnetic resonance (EPR), optical absorption, and photoluminescence (PL) spectroscopy, a strong correlation is observed between the green 510 nm emission, the free-carrier concentration, and the density of singly ionized oxygen vacancies in commercial ZnO phosphor powders.... (Read more)
- 33. J. Appl. Phys. 79, 7983-7990 (1996) , “Mechanisms behind green photoluminescence in ZnO phosphor powders”, K. Vanheusden, W. L. Warren, C. H. Seager, D. R. Tallant, J. A. Voigt, B. E. GnadeWe explore the interrelationships between the green 510 nm emission, the free-carrier concentration, and the paramagnetic oxygen-vacancy density in commercial ZnO phosphors by combining photoluminescence, optical-absorption, and electron-paramagnetic-resonance spectroscopies. We find that the green... (Read more)
- 34. Appl. Phys. Lett. 67, 1280 (1995) , “Impact of Pb doping on the optical and electronic properties of ZnO powders”, K. Vanheusden, W. L. Warren, J. A. Voigt, C. H. Seager, and D. R. TallantElectron paramagnetic resonance (EPR), optical absorption, and photoluminescence (PL) spectroscopy have been combined to characterize Pb-doped ZnO ceramic powders. We observe a decrease in the 2.26 eV emission peak and a concomitant smearing of the band edges, narrowing the effective gap of the... (Read more)
- 35. J. Appl. Phys. 74, 5901-5903 (1993) , “The nature of donor conduction in n-GaN”, M. Asif Khan, D. T. Olson, J. N. Kuznia, W. E. Carlos, J. A. Freitas, JrSingle crystal GaN thin films resulting from various deposition techniques are usually dominated by residual donors. To date, the true nature of this donor conduction is not known. Nitrogen vacancies, residual oxygen, and growth defects are cited as potential causes for the residual n-type... (Read more)
- 36. Physica B 116, 583-593 (1983) , “Investigations of well defined dislocations in silicon”, H. Alexander, C. Kisielowski-Kemmerich, E. R. WeberThe velocity v of dislocation half-loops introduced into swirl-free floating-zone grown undoped silicon has been measured at 420°C in the resolved shear stress range 30 <Ď<300 MPa. Clearly impurity atoms interact with dislocations in this material. Using the starting value of v we found the two types of 60° dislocations, which are distinguished by the sequence of their partials, to have different velocities. Furtheron the velocity depends not only on Ď, but also on the elastic strain of the lattice. In the second part the papers review EPR spectroscopy of plastically deformed silicon and collects new results on the activity of dislocations in this material as trapping / recombination centers (decay of photo-EPR, photoluminescence, EBIC microscopy and photoplastic effect). (Read more)
- 37. J. Lumin. 12-13, 441-445 (1976) , “ESR and luminescence of trapped hole centers in ZnO and SnO2”, E. Mollwo , D. ZwingelIn SnO2 single crystals acceptor centers are found upon incorporation of Al3+ and Ga3+ ions at cation sites. After UV-excitation, holes, trapped at these centers, give rise to polarized luminescence and thermoluminescence. The structure of the centers is analysed by ESR and compared with similar... (Read more)
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