A PHOTOLUMINESCENCE AND PHOTOCAPACITANCE STUDY OF GAAS-IN AND GAAS-SBLAYERS GROWN BY LIQUID-PHASE EPITAXY

Results of Hall, photoluminescence and photocapacitance measurements p erformed on GaAs layers grown by liquid-phase epitaxy (LPE) and doped with various amounts of indium (In) and antimony (Sb) are presented. H all measurements show that such doping marginally enhances the mobilit y in a certain optimum doping range. Near-band-edge photoluminescence spectra indicate the presence of C(As) and Si(As) as major acceptor im purities in lightly In-doped material. The latter impurity is not dete cted in heavily In-doped GaAs layers or in Sb-doped layers with either low and high doping density. Photocapacitance measurements reveal the presence of hole traps A and B, reported previously in undoped LPE Ga As. Indium doping reduces the total density of these traps. Furthermor e, Sb doping induces a very sharp fall in the density of trap B. The r esults indicate that the hole trap B may be related to a Ga(As) antisi te defect.