SYNTHESIS GALLIUM NITRIDE THIN FILMS BY PULSED LASER DEPOSITION AS AMMONIA (NH3) GAS SENSOR

GaN thin films were deposited on silicon substrate (Si) by pulse laser deposition in a nitrogen atmosphere to use as a gas sensor for detection Ammonia (NH3) gas. Surface morphology of gallium nitride nano thin films were characterized by atomic force microscopy (AFM). The film appears homogenous and the distribution and grain shapes is nearly uniform. High density of nanostructure GaN was created as shown in field emission scan electron microscopy (FESEM) image. XRD measurement showed that GaN have a hexagonal structure. The elemental composition of materials was identified by use of Energy Dispersive X- Ray Analysis (EDX). The average concentration of nitrogen according to EDX analysis for the samples are increase with increasing number of laser pulses. Optical measurements were performed to measure the band gap by UV-visible spectroscopy. The gas sensitivity for NH3 gas were measured for fabricated gas sensor device as a function of concentration.