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Quantum efficiency and radiative lifetime in degenerate n-type GaAs
Solid State Communications, Vol. 35, pp. i—v. Pergamon Press Ltd. 1980. Printed in Great Britain.
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published) should be cited in references to material quoted from this section prior to the publication of the relevant article. 1.
U centers, thus completely bleaching the colored crystal. By these photo-reactions, high contrast visible images can be produced which are stable under visible light at RI, and are thermally stable up to 650°C. Besides the optical information-storage aspect, these photo-reactions can be used for controlled production of UA centers if the crystal contains alkali-ion impurities like Na~.
DIFFUSION OF 51Cr IN Cr-DOPED MgO G.W. Weber, W.R. Bitler and V.S. Stubican, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, U.S.A.
An arc fusion technique was used to grow single crystals of MgO and Cr-doped MgO. Diffusion coeffients for 51Cr in Cr-doped single crystals were measured at three temperatures 1383, 1444 and 1495°Cusing a high specific activity isotope 51Cr. An approximately linear relationship between the concentration of Crions in MgO and diffusion coefficients of 51Cr was obtained. it is shown that the activation energy of 19.6 kcal mol’ obtained for the doped crystals is the difference between the energy for motion and the energy for association of the Cr-vacancy complexes. Using a previously determined value of 39.9 kcal mol’ for the energy of motion, the energy of association for the Cr-vacancy complex is calculated to be 20.3 ±3 kcal mol~or 0.88 ±0.13 eV.
Received 23 January 1980 3.
The hole lifetime, the radiative lifetime, the nonradiative lifetime, and the internal quantum efficiency in degenerate n-type GaAs crystals have been investigated with a simplified model of degenerate semiconductors, in which the recombination constant B is approximately proportional to the 13/8 power of the electron density. In n-type GaAs at 77 K, the radiative lifetime reaches a minimumequal to 4 x iO~sec at 6 x
Received 17 December 1979 Revised 2May 1980
2.
QUANTUM EFFICIENCY AND RADIATIVE LIFETIME IN DEGENERATE n-TYPE GaAs H. Van Cong, Institut d’Electronique Fondamentale, Lab. Associé au CNR.S, Bat. 220, Université de Paris XI, 91 405 Orsay, France.
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PHOTOCHEMISTRY AND REACTIONS OF OFF DEFECTS AND F CENTERS IN ALKALI HALIDES Spero Penha Morato and Fritz LUty, Physics Department, University of Utah, Salt Lake City, UT 84112, U.S.A.
10 cm, and the internal exhibits a maximum equal toquantum 50% at 8efficiency x 1017 cm3, in good agreement with the theoretical prediction of Dumke and the experiments of Cusano. At high impurity concentrations, the polytropy effect is taken into account in the case of GaAs crystals doped with
Additively colored KU : OFFcrystals show under combined u.v. and visible irradiation an irreversible destruction of F centers and visible absorption. Tim process, which is effective over the whole temperature range 4—300 K, was studied systematically in terms of the reaction efficiency and products using u.v.-visible and infrared (local mode) spectroscopy. The u.v. photo-dissociation of OFF defects and photo-ionization of F centers produce a combined net effect, in which at higher temperatures all F centers are converted into
tellurium and selenium. Finally, it is suggested that, for a given high concentration, the internal quantum efficiency increases with increasing temperature, in accordance with the observed results. Received 26 Febmary 1980 Revised 15 May 1980
i
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published) should be cited in references to material quoted from this section prior to the publication of the relevant article. 1.
U centers, thus completely bleaching the colored crystal. By these photo-reactions, high contrast visible images can be produced which are stable under visible light at RI, and are thermally stable up to 650°C. Besides the optical information-storage aspect, these photo-reactions can be used for controlled production of UA centers if the crystal contains alkali-ion impurities like Na~.
DIFFUSION OF 51Cr IN Cr-DOPED MgO G.W. Weber, W.R. Bitler and V.S. Stubican, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, U.S.A.
An arc fusion technique was used to grow single crystals of MgO and Cr-doped MgO. Diffusion coeffients for 51Cr in Cr-doped single crystals were measured at three temperatures 1383, 1444 and 1495°Cusing a high specific activity isotope 51Cr. An approximately linear relationship between the concentration of Crions in MgO and diffusion coefficients of 51Cr was obtained. it is shown that the activation energy of 19.6 kcal mol’ obtained for the doped crystals is the difference between the energy for motion and the energy for association of the Cr-vacancy complexes. Using a previously determined value of 39.9 kcal mol’ for the energy of motion, the energy of association for the Cr-vacancy complex is calculated to be 20.3 ±3 kcal mol~or 0.88 ±0.13 eV.
Received 23 January 1980 3.
The hole lifetime, the radiative lifetime, the nonradiative lifetime, and the internal quantum efficiency in degenerate n-type GaAs crystals have been investigated with a simplified model of degenerate semiconductors, in which the recombination constant B is approximately proportional to the 13/8 power of the electron density. In n-type GaAs at 77 K, the radiative lifetime reaches a minimumequal to 4 x iO~sec at 6 x
Received 17 December 1979 Revised 2May 1980
2.
QUANTUM EFFICIENCY AND RADIATIVE LIFETIME IN DEGENERATE n-TYPE GaAs H. Van Cong, Institut d’Electronique Fondamentale, Lab. Associé au CNR.S, Bat. 220, Université de Paris XI, 91 405 Orsay, France.
—
PHOTOCHEMISTRY AND REACTIONS OF OFF DEFECTS AND F CENTERS IN ALKALI HALIDES Spero Penha Morato and Fritz LUty, Physics Department, University of Utah, Salt Lake City, UT 84112, U.S.A.
10 cm, and the internal exhibits a maximum equal toquantum 50% at 8efficiency x 1017 cm3, in good agreement with the theoretical prediction of Dumke and the experiments of Cusano. At high impurity concentrations, the polytropy effect is taken into account in the case of GaAs crystals doped with
Additively colored KU : OFFcrystals show under combined u.v. and visible irradiation an irreversible destruction of F centers and visible absorption. Tim process, which is effective over the whole temperature range 4—300 K, was studied systematically in terms of the reaction efficiency and products using u.v.-visible and infrared (local mode) spectroscopy. The u.v. photo-dissociation of OFF defects and photo-ionization of F centers produce a combined net effect, in which at higher temperatures all F centers are converted into
tellurium and selenium. Finally, it is suggested that, for a given high concentration, the internal quantum efficiency increases with increasing temperature, in accordance with the observed results. Received 26 Febmary 1980 Revised 15 May 1980
i