DISORDER-INDUCED ANDERSON LOCALIZATION IN GAAS1-XPX

We report low-temperature photoluminescence studies of undoped GaAs//1// minus //xP//x alloys. Arguments are presented for the identification of the strongly asymmetrically shaped peak with the recombination of electrons and holes bound to different regions of the alloy. It is proposed that at low temperatures, the carriers are subject to Anderson localization below a mobility edge in the potential wells which are induced by the fluctuating alloy potential. Variations in its properties with varying alloy composition suggest that the localization effects are primarily related to electrons with X-conduction band character.