Molecular Beam Epitaxy of GaSb on GaAs Substrates with Compositionally Graded LT-GaAsxSb1-x Buffer Layers**Supported by the National Basic Research Program of China under Grant Nos 2015CB351902, 2015CB932402 and 2012CB619203, the National Natural Science Foundation of China under Grant Nos 61177070, 11374295 and U1431231, and the National Key Research Program of China under Grant No 2011ZX01015-001.

Abstract

We investigate the molecular beam epitaxy growth of GaSb films on GaAs substrates using compositionally graded GaAsxSb buffer layers. Optimization of GaAsxSb growth parameter is aimed at obtaining high GaSb crystal quality and smooth GaSb surface. The optimized growth temperature and thickness of GaAsxSb layers are found to be 420°C and 0.5 μm, respectively. The smallest full width at half maximum value and the root mean square surface roughness of 0.67 nm over 2 × 2 μm2 area are achieved as a 250 nm GaSb film is grown under optimized conditions.