Formation of an atomically flat surface of ZnSe on GaAs(001) by metalorganic vapor phase epitaxy

Surface morphologies of pseudomorphic ZnSe on GaAs (001) grown by metalorganic vapor phase epitaxy hale been studied by atomic force microscopy. The observation of ZnSe gown at 400, 450 and 500 degrees C reveals that the growth mode below 450 degrees C is 2 dimensional (2D), while that at 500 degrees C is highly 3D. In particular, growth at 450 degrees 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 degrees C and post-growth annealing at the same temperature in Se ambient.