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101.
The high-temperature thermal properties of the ternary oxides LiGaO2 and NaGaO2 are studied by simultaneous differential thermal analysis and thermogravimetry between room temperature and about 1700 °C. For the melting temperature of LiGaO2 a value of 1595 ± 10 °C is determined. NaGaO2 undergoes a solid state phase transition at 1280 ± 10 °C and melts at 1395 ± 10 °C. 相似文献
102.
103.
H. Neumann 《Crystal Research and Technology》1993,28(1):73-82
Theoretical relations are derived for the amplitude of the photoacoustic signal of a gas-coupled cell for thick semiconductor samples including the influence of multiple reflections of light within the sample. It is shown that in the range of low absorption coefficients characteristic of impurity absorption spectra the sensitivity of the cell can be enhanced by using a highly reflecting metal as backing material. Numerical estimates for CuInSe2 are given to illustrate this effect. 相似文献
104.
Doz. Dr. sc. C. Ascheron Doz. Dr. sc. H. Neumann Prof. Dr. sc. G. Kühn 《Crystal Research and Technology》1991,26(3):273-281
Implantation induced changes of the microhardness are studied in GaP single crystals which were bombarded with ions in the range of mass numbers M = 1–40. It is observed that point defects and incorporated hydrogen have a stronger hardening effect. The effect of defect complexes is lower, and amorphized layers are softer than crystalline layers. 相似文献
105.
Infrared reflectivity spectra of thermally oxidized CuInSe2 single crystals are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. A Kramers-Kronig analysis of the spectra reveals seven vibrational modes with frequencies which agree with mode frequencies in In2O3. No vibrational modes due to Cu–O and Se–O bonds could be observed. The results obtained are compared with previous studies of oxidized CuInSe2 crystals. 相似文献
106.
H. Neumann 《Crystal Research and Technology》1991,26(8):1001-1010
The lattice vibrations of the AIIBIII2CVI4 semiconductors with defect-chalcopyrite structure are treated in a simplified version of the Keating model considering only interaction with nearest neighbours and assuming that all anions occupy their ideal lattice sites. It is found that in this model the frequencies of the nonpolar and polar modes with highest energy are determined by the properties of the BIII–CVI sublattice alone. The frequencies of all the other optical modes depend not only on the AII–CVI and BIII–CVI interactions but are also influenced by the presence of the ordered array of vacancies. The results obtained are compared with previous model considerations. 相似文献
107.
108.
109.
A. Zegadi M. V. Yakushev H. Neumann M. A. Slifkin R. D. Tomlinson 《Crystal Research and Technology》1995,30(4):517-530
Photoacoustic spectra of cleaved, polished and etched, and air-annealed n-type CuInSe2 single crystals are measured at different frequencies between 30 and 312 Hz. The spectra related to the bulk of the crystals exhibit five structures due to defects that are also present in p-type crystals. Polishing and etching as well as subsequent air annealing at 100, 200 and 300 °C reveal rather complex changes of the defect equilibrium in the near-surface region of the crystals which include both relative concentration changes of existing defects and creation of new defects. The results for polished and etched crystals correspond to trends expected from etching induced local modifications of the composition and structure as revealed by electron spectroscopies and ion channeling. Air annealing is found to affect all existing defects and to create up to five new defects which cannot be explained in terms of the related point defect model proposed by CAHEN and NOUFI. 相似文献
110.
M. V. Yakushev A. Zegadi H. Neumann P. A. Jones A. E. Hill R. D. Pilkington M. A. Slifkin R. D. Tomlinson 《Crystal Research and Technology》1994,29(3):427-437
The defect properties of p-type CuInSe2 single crystals hydrogenated by diffusion from a plasma source are investigated using the Rutherford backscattering/channeling technique and photoacoustic spectroscopy. Plasma hydrogenation is found to produce severe lattice damage, to affect the intrinsic defect equilibrium in the near surface region of the crystals and to create an additional donor. A defect formation model including both defect passivation by hydrogen and damage induced defect creation is proposed to explain the experimental data. The thermal stability of the property modifications is limited to temperatures below about 100 °C. 相似文献