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Full-Text Articles in Physics
Hole Transport In Pure And Doped Gaas, H. J. Lee, David C. Look
Hole Transport In Pure And Doped Gaas, H. J. Lee, David C. Look
Physics Faculty Publications
We have used a two-band model (heavy and light holes) to calculate the transport properties ofp-type GaAs. The scattering mechanisms included are acoustic-mode deformation potential, acoustic-mode piezoelectric potential, polar- and nonpolar-mode deformation potential, ionized impurity, and space charge. Interband scattering is included explicitly for the optical phonons and phenomenologically for the acoustic phonons. The intraband polar optical-mode scattering, for which a relaxation time cannot be defined, was calculated by using the numerical method of Fletcher and Butcher. The acoustic deformation-potential parameter and the coupling coefficient for interband scattering were calculated by fitting the theory to Hall-mobility data for both pure …
Low Compensation Vapor-Phase Epitaxial Gallium-Arsenide, P. C. Colter, David C. Look, D. C. Reynolds
Low Compensation Vapor-Phase Epitaxial Gallium-Arsenide, P. C. Colter, David C. Look, D. C. Reynolds
Physics Faculty Publications
Vapor phase epitaxial gallium arsenide (GaAs) layers, with lower compensation ratios than any reported heretofore, have been reproducibly grown by the Ga/H2/AsCl3 method. One of these samples has been studied extensively by electrical measurements and shows an acceptor concentration of (2.0 ± 0.7)X1013 cm-3 , and a compensation rate of NA/ND = 0.06 ± 0.02. These numbers are supported by magnetophotothermal spectroscopy and photoluminescence measurements. The preparation involves growth on [211A] substrates, and a pregrowth bakeout of the Ga source, which results in a significantly lower Zn acceptor concentration in the layer. …
A Study Of The 0.1-Ev Conversion Acceptor In Gaas, David C. Look, Gernot S. Pomrenke
A Study Of The 0.1-Ev Conversion Acceptor In Gaas, David C. Look, Gernot S. Pomrenke
Physics Faculty Publications
Two semi-insulating liquid-encapsulated Czochralski GaAs cyrstals, one Cr-doped and the other undoped, were annealed at 750°C for 15 min in flowing H2. Each sample converted to conducting p type in the near-surface region, due to the formation of acceptors at E∪ + 0.1 eV. We have studied this phenomenon by electrical, optical, and analytical profiling techniques, and have determined conclusively that the acceptors in our samples are not related to Mn accumulation, a commonly accepted explanation. It is argued that the O.I-e V center may arise from several possible sources, each exhibiting a VGa -like state at …
Defect Nature Of The 0.4-Ev Center In O-Doped Gaas, David C. Look, S. Chaudhuri, J. R. Sizelove
Defect Nature Of The 0.4-Ev Center In O-Doped Gaas, David C. Look, S. Chaudhuri, J. R. Sizelove
Physics Faculty Publications
We have studied the Ec - 0.4 e V center in O-doped GaAs by a combination of temperature-dependent Hall-effect measurements, spark-source mass spectroscopy, and secondary-ion mass spectroscopy. The conclusion is that neither 0 nor any other impurity can account for the O.4-eV center; therefore, it is a pure defect.
Seam Wave Characteristics In An Eastern U.S. Coal, Paul J. Wolfe, Timothy G. Holdeman, Benjamin H. Richard
Seam Wave Characteristics In An Eastern U.S. Coal, Paul J. Wolfe, Timothy G. Holdeman, Benjamin H. Richard
Physics Faculty Publications
No abstract provided.
Nitrogen Escape From Mars, Jane L. Fox, Alexander Dalgarno
Nitrogen Escape From Mars, Jane L. Fox, Alexander Dalgarno
Physics Faculty Publications
The escape rate of nitrogen from Mars is calculated to be 2.3×105 s−1 for low solar flux conditions and 8.9×105 s−1 for high solar flux conditions. The major source of energetic atoms is dissociative recombination of ground state and vibrationally excited N2+ ions. The measured 15N/14N isotope ratio can be reproduced by postulating an early dense atmosphere during which little differentiation occurred.