Surface band bending, nitrogen-vacancy-related defects, and 2.8-eV photoluminescence band of (NH4)2Sx-treated p-GaN

We have employed the photoluminescence and x-ray photoelectron spectroscopy measurements to study the effects of (NH4)(2)S-x treatment on the p-type GaN (p-GaN). After (NH4)(2)S-x treatment, we found. that the reduction of the surface state, related to nitrogen-vacancy defects on the p-GaN surface, led to a reduction in surface band bending by 0.25 eV. The surface band bending reduction and surface state reduction, caused by the (NH4)(2)S-x surface treatment could be useful for the formation of ohmic and Schottky contacts between the metal and p-GaN layers. In addition, the intensity of the 2.8-eV photoluminescence band depended on the amount of nitrogen vacancy of p-GaN, which was also investigated in this study. (C) 2002 American Institute of Physics. [DOI: 10.1063/1.4533857].