Carrier Pathway for Photoelectrochemical Water Oxidation with Intermediate State in n-type GaN Compared with Route of Anodic Corrosion

Photoelectrochemical water splitting is a solar-to-chemical energy conversion technique. However, when n-type nonoxide semiconductors are used as photoanodes, they corrode, which is a competitive reaction with water oxidation. To evaluate these competing reactions, the optical properties (photoluminescence) of n-type GaN were examined and compared with the results of a photoelectrochemical analysis. The intermediate hole trap state associated with the yellow luminescence of GaN was found to be a candidate for the carrier transfer site for water oxidation. The hole for electrode corrosion was estimated to have a different pathway from this trap site and to be associated with the hole located at the valence band edge.

Automated summary

The optical properties and results of photoelectrochemical analysis of n-type GaN were examined, revealing that the intermediate hole trap state associated with yellow luminescence could potentially be a carrier transfer site for water oxidation. It was estimated that the hole responsible for electrode corrosion follows a different pathway and is associated with the hole located at the valence band edge.