Formation of an Atomically Flat Surface of ZnSe on GaAs (001) by Metalorganic Vapor Phase Epitaxy

Abstract

Surface morphologies of pseudomorphic ZnSe on GaAs (001) grown by metalorganic vapor phase epitaxy have been studied by atomic force microscopy. The observation of ZnSe grown at 400, 450 and 500°C reveals that the growth mode below 450°C is 2 dimensional (2D), while that at 500°C is highly 3D. In particular, growth at 450°C is in the layer-by-layer mode. These observations are interpreted in terms of temperature-enhanced migration of Zn adatoms and evaporation of Se from the ZnSe surface. An atomically flat ZnSe surface which consists of wide terraces without small 2D islands can be obtained by growing at 450°C and post-growth annealing at the same temperature in Se ambient.