Luminescence in Silicon-Doped GaAs Grown by Liquid-Phase Epitaxy

• Published in: Journal of applied physics 1968-03, Vol.39 (4), p.2006-2011
• Main Authors: Kressel, H., Dunse, J. U., Nelson, H., Hawrylo, F. Z.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1656480

The radiative processes in closely compensated GaAs doped with Si (p-type) and Si+Te (n-type) have been studied by photoluminescence between 300° and 77°K. These materials were grown by liquid-phase epitaxy. The results strongly suggest that Si introduces two acceptor levels in GaAs with ionization energies of approximately 30 meV and ∼100 meV. In the n-type material containing Si and Te only the radiative transition involving the deeper acceptor is observed (hvp∼1.44 eV at 77°K). In moderately Si-doped, p-type material (∼1018 cm−3 range), transitions involving both levels are observed. The apparent ionization energy of the deeper level moves to higher energies with increasing Si concentration while the shallow acceptor band appears to merge with the valence band. In the p-type material, the electron transitions are assumed to originate at deep states (>40 meV) in the ``tail'' of states below the conduction band introduced by the high Si donor concentration. An intense broad emission band centered in the range 1.26 to 1.23 eV at 77°K is observed in some p-type specimens. This band is attributed to an acceptor level 230±20 meV above the valence band. It is tentatively suggested that it involves an As vacancy or As vacancy complex.