Band bowing and band alignment in InGaN alloys

Abstract

We use density functional theory calculations with the HSE06 hybrid exchange-correlation functional to investigate InGaN alloys and accurately determine band gaps and band alignments. We find a strong band-gap bowing at low In content. Band positions on an absolute energy scale are determined from surface calculations. The resulting GaN/InN valence-band offset is 0.62 eV. The dependence of InGaN valence-band alignment on In content is found to be almost linear. Based on the values of band gaps and band alignments, we conclude that InGaN fulfills the requirements for a photoelectrochemical electrode for In contents up to 50%.