Preparation and photoelectrochemical properties of GaN-based TiO2 nanorod heterojunctions

Abstract

GaN-based indium (In)-doped TiO₂ nanorod heterojunctions (GaN/In-TiO₂) are heteroepitaxially grown on C-plane sapphires by metal–organic chemical vapor deposition (MOCVD). Compared with GaN-based undoped TiO₂ nanorod heterojunctions (GaN/u-TiO₂), GaN/In-TiO₂ shows decreased photoluminescence (PL) intensity, increased photocurrent density and reduced charge transfer resistance, meaning that the doping of In can effectively suppress the recombination of photogenerated electron–hole pairs and improve the separation and transfer efficiency of charge. Importantly, GaN/In-TiO₂ exhibits a lower turn-on voltage, larger H₂ production and higher faradaic efficiency (FE) compared with GaN/u-TiO₂.