Comparative analysis of morphology and optical properties of GaN layers on sapphire

Abstract

A comprehensive analysis of gallium nitride layers grown by the metal-organic vapor-phase epitaxy technique on sapphire substrates is performed. The spectrum of photoluminescence of these layers corresponds to the width of the energy gap of gallium nitride. Comparative analysis of the layer’s surface with the interferometry, scanning electron microscopy, and atomic-force microscopy has revealed characteristic inhomogeneities on it. The deposition of a thin metal film on the surface has allowed one to identify them as the inhomogeneities of the work function and not of the surface relief.