Metalorganic molecular beam epitaxy growth and etching of GaSb on flat and high-index surfaces using trisdimethylaminoantimony

Abstract

Metalorganic molecular beam epitaxy growth and etching of GaSb using triethylgallium (TEGa), trisdimethylaminoantimony (TDMASb) and elemental antimony (Sb 4) on flat and high-index surfaces are investigated. A higher growth rate is obtained on the ( n11) surface ( n = 5, 4, 3) using TEGa and Sb 4, indicating that the incorporation efficiency of Ga atoms is enhanced on these surfaces. This is explained by taking into account the steps where the decomposition of TEGa is enhanced. When only TDMASb is supplied, GaSb surfaces are etched for all misoriented GaSb substrates studied. On the other hand, when TEGa is simultaneously supplied in addition to TDMASb, the surface reaction is changed from etching to growth on the n = 5, 4, 3 surfaces. This is because the growth of GaSb is increased more than the etching by TDMASb on these surfaces. 77 K photoluminescence spectra show a sharp band-to-band transition peak at about 804 meV with a full width at half maximum of less than 9 meV indicating good optical quality. Unintentionally doped GaSb epilayers show p-type conduction with a 77 K hole mobility of 820 cm 2/V s and a hole concentration as 1.2 × 10 16cm −3.