Synthesis and optical characterization of c-axis oriented GaN thin films on amorphous quartz glass via sol-gel process

c-Axis oriented GaN nanocrystalline thin films were fabricated by nitridation of three different thin films of α-GaO(OH), α-Ga2O3 or β-Ga2O3 obtained by sol-gel technique on amorphous quartz glass substrates. All these GaN thin films showed near band edge emission at 390 nm and yellow luminescence at 570 nm. The crystalline nature and c-axis orientation as well as luminescence properties of the GaN thin films increased by several times by using a buffer layer of GaN on the substrate.