Electronic structure of GaN nanowall network analysed by XPS

Abstract

This work examines the changes in bonding of GaN nanowall network samples with varying morphology grown by rf-plasma assisted molecular beam epitaxy system. X-ray photoelectron spectroscopy is employed to study the valence band spectra of two samples and the difference in bonding with change in morphology is observed. Compared to a standard epilayer, the nanostructured samples display a higher binding energy for different hybridization levels appearing near the top of valence band. Higher than statistical branching ratio of Ga 2p spin split levels is also observed unlike in the case of epilayer. The higher bonding energy is understood as having more stable electronic structure which is possible because of reduction of defects in the nanostructured films. (C) 2014 Elsevier B.V. All rights reserved.