Gallium nitride films synthesized by reactive pulsed laser deposition from a GaAs target

Abstract

We demonstrated the feasibility of the growth of GaN thin films from polycrystalline GaAs using reactive pulsed laser deposition. The films were grown on Si (1 00) substrates at temperatures lower than 80 °C. A bulk of polycrystalline GaAs was used as target. Reactive nitrogen plasma was provided by electron cyclotron resonance (ECR) microwave discharge in pure nitrogen gas to assist the film growth. Composition analysis showed that the grown films are slightly N-rich, and arsenic can hardly be detected. A strong absorption peak corresponding to Ga-N stretching vibration in the hexagonaltype GaN crystals is clearly resolved from the JR absorption spectrum. The films exhibit transparency in the visible and near-JR regions. The band gap of the films was determined to be about 3.4 eV. When excited by 325-nm light at 10.2 K, the grown films luminesce in the blue region.