Effect of temperature on GaN films deposited on graphite substrates at low-temperature

Highly-quality GaN films were deposited on graphite substrates using electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system (ECR-PEMOCVD) at low temperature. The influence of temperature on the properties of GaN films was investigated systematically by X-ray diffraction analysis (XRD), scanning electron microscope (SEM), and room temperature photoluminescence (PL), respectively. Results indicated that the dense and uniformed GaN films with highly c-axis preferred orientation were successfully achieved on graphite substrates under optimized deposition temperature of 450 ̊C. In addition, the relatively good ohmic contact between GaN and graphite was demonstrated by current–voltage (I–V) characteristics measurement.