Ga Adlayer Coverage and Surface Morphology Evolution during GaN Growth by Plasma-assisted Molecular Beam Epitaxy

Abstract

-Ga adlayer coverage and surface morphology evolution during GaN grown by PAMBE are studied on an atomic scale. Ga adlayer coverage, which is closely dependent on the Ga/N flux ratios, is found to be a very important factor in determining the surface morphology. A laterally contracted Ga bilayer is able to stabilize the GaN surface to produce the minimum pit density. Such an energetically favorable adlayer can only be achieved under certain Ga/N ratio, which is calculated from the kinetic rates of Ga adsorption and desorption.