SPATIAL-DISTRIBUTION OF IN DURING THE INITIAL-STAGES OF GROWTH OF INAS ON GAAS(001)-C(4X4)

The initial stages in the growth of InAs by molecular beam epitaxy (MB E) on GaAs(001)-c(4x4) have been studied by in situ scanning tunnellin g microscopy (STM) and reflection high energy electron diffraction (RH EED). Deposition of 0.1 ML at 420 degrees C gives rise to a low number density of two dimensional (2D) islands on top of domains of locally disordered (1 x 3) structures which decorate the step edges. The size of the (1 x 3) domains increase as more InAs is deposited, consistent with the development of a (1 x 3) RHEED pattern. The results show that a 2D growth mode operates with strong evidence for alloying in the su rface layer. The spatial distribution of In in the surface layer has a lso been investigated by varying the substrate temperature for InAs de position. The implication is that growth at similar to 420 degrees C p rovides the optimal condition for growing high quality InAs monolayers on GaAs(001).