The effect of grain boundaries on electrical conductivity in thin GaN layers

The effect of grain boundaries on electrical properties of thin GaN layers is studied by photoconductivity and its functional dependence on surface ph otovoltage, and by resistance changes produced by ion implantation damage. These two independent experiments provide strong evidence that the conducti vity in GaN can be described by the Grain Boundary Controlled Transport mod el. According to this model, charged interface states at the grain boundari es form potential barriers for inter-grain conduction.