Surface morphology of MOCVD-grown GaN on sapphire

Thin GaN layers on sapphire were grown by metal organic chemical vapor deposition (MOCVD) and characterized by X-ray diffraction and photoluminescence. AFM and SEM studies show flat surfaces with pyramid-like and truncated pyramid-like hexagonal hillocks. Their inclined faces, which form low angles (4.5/spl deg/-10.5/spl deg/) with the (0001) plane, are smooth and continuous. They can be interpreted as high index {011~l} vicinal surfaces.