Alternating current bias-assisted photoenhanced oxidation of n-GaN in dionized water

Patterned oxidation of n-GaN in water at room temperature is achieved by using an imprint technique and an alternating current (ac) bias-assisted photoelectrochemical process. Mold is fabricated by a double-side polished sapphire coated with indium tin oxide thin film to be an electrode for electric conduction and allow the high transparency for ultraviolet light. The growth rate of gallium oxide-based material of around 12 nm/min could be achieved when an ac bias of 3 V with a duty cycle of 90% was applied to the system. The film is determined by high-resolution transmission electron microscopy and selected area electron diffraction pattern.