Zinc oxide as a contact material for p-GaN

The fabrication procedure of transparent and conducting ZnO films yielding ohmic contacts to p-GaN has been developed. The microstructure and electronic properties of p-GaN/ZnO interface were studied using atomic force and electron transmission microscopies, and X-ray photoelectron spectrometry. The observed ohmic behaviour is explained in terms of formation of a tunnelling p-GaN/ n/sup +/-ZnO junction.