Evaluation of GaN growth improvement techniques

Recently good quality epilayers of GaN have been grown heteroepitaxially on different substrates using various growth techniques. Buffer layers, epitaxial lateral overgrowth and pendeo-epitaxial overgrowth are the most important and effective techniques that made a revolution in the improvement of the quality and properties of the GaN materials, led to obtain single crystalline GaN films with a smooth surface and reasonable electrical and optical properties. The aim of this paper is to review the different techniques used to improve the quality and properties of the GaN materials, which opened the way for GaN and itʹs alloys to be used in a countless number of applications.