Molecular-beam epitaxy of GaSb on 6°-offcut (0 0 1) Si using a GaAs nucleation layer

Abstract

We studied and optimized the molecular beam epitaxy of GaSb layers on vicinal (0 0 1) Si substrates using a GaAs nucleation layer. An in-depth analysis of the different growth stages under optimized conditions revealed the formation of a high density of small GaAs islands forming a quasi-two-dimensional layer. GaSb then nucleated atop this layer as three-dimensional islands before turning to two-dimensional growth within a few nanometers. Moreover, reflexion high-energy electron diffraction revealed a fast relaxation of GaAs on Si and of GaSb on GaAs. The GaSb layer quality was better than that of similar layers grown on Si through AlSb nucleation layers.