Electrical and photoluminescence properties of bulk GaAs after surface gettering

The successful results on surface gettering of background impurities and defects in 1.6 mm thick (111) GaAs wafers have been obtained. For the gettering, the wafers were coated by a 1000 Å thick yttrium film either on one side or on both sides followed by a heat treatment. It has allowed the electron concentration to decrease from (1–2)´10 15 cm -3 down to 10 8 –10 10 cm -3 and the mobility to increase from 1500–2000 cm 2 V -1 s -1 up to 7000 cm 2 V -1 s -1 at 300 K. The distribution profiles of the electron concentration and of the hole effective lifetime throughout the wafer thickness as well as photoluminescence spectra at 2 K have been presented