Low - Temperature Defect - Induced Aging of GaAs Grown by Molecular Beam Epitaxy

Abstract

Degradation in optical and electrical properties has been observed for high-purity and high-mobility p-type GaAs layers which contain significant concentrations of an unidentified shallow acceptor-like defect, labeled “A”, that is frequently incorporated in crystals grown by molecular beam epitaxy. Low-temperature photoluminescence and variable temperature Hall-effect measurements were employed to monitor the aging process in samples stored for about one year at room temperature. Profound changes in the exciton recombination spectra, indicative of increasing concentration of the “A” defect, have been accompanied by a decrease in hole mobility and an increase in carrier concentration. These results are discussed in the context of the acceptor-pair defect model, originally proposed by Eaves and Halliday [J. Phys. C: Solid State Phys. 17, L705 (1984)].

Species dependence of passivation and reactivation of acceptors in hydrogenated GaAs

“…6 , 30 The passivation of minority acceptors in n-type GaA:; can also be explained using Hopfield's mode1. The constraint on formation of neutral acceptors renders the passivated acceptor impurities inefficient as radiative recombination centers, thus explaining the decay of acceptor-related luminescence after hydrogenation.…”