Bias-assisted photoelectrochemical oxidation of <i>n</i>-GaN in H2O

Abstract

Growth of gallium oxide on n-GaN was realized in H2O by bias-assisted photoelectrochemical (PEC) oxidation using Al as a counterelectrode instead of a Pt commonly used in the PEC process. Although the growth of the oxide was not observed at below 2 V, the initial oxide growth rate of 8.7 nm/min was shown at a bias of 15 V and ultraviolet light intensity of 300 mW/cm2. However, the growth rate lowered and oxide thickness was saturated to 340 nm. The saturated oxide thickness and initial growth rate were increased with the applied bias. The homogeneous oxide growth and near stoichiometric composition of Ga2O3 were observed in Auger electron spectroscopy analysis results.