SULFUR-DOPING OF GASB GROWN BY ATMOSPHERIC-PRESSURE MOVPE

Sulphur-doped GaSb epitaxial layers are grown on GaSb and GaAs substra tes by atmospheric pressure MOVPE. Trimethylgallium and trimethylantim ony are used as the Ga and Sb sources, respectively. Hydrogen sulphide (1% H2S diluted in hydrogen) is employed as the sulphur source. The mo le fraction of H2S in the reactor ranging from 6.1 x 10(-6) to 1.2 x 1 0(-4) results in the hole concentrations from 2.8 x 10(17) to 2.5 x 10 (18) cm(-3), respectively. Low temperature (T = 5 K) photoluminescence measurements show a sulphur-related transition S-1 near 732 meV indic ating that sulphur is successfully incorporated into GaSb. The PL spec tra of the samples grown with a H2S mole fraction larger than 6.2 x 10 (-5) consist only of a native acceptor transition A and a sulphur-rela ted transition S-1. The position of S-1 transition is independent of t he H2S mole fraction. The ratio of the intensity of the sulphur-relate d transition S-1 to the that of the transition A increases from 0 up t o 1.5 with increasing H2S mole fraction.