Quantum dot activated indium gallium nitride on silicon as photoanode for solar hydrogen generation

Abstract

Nitride alloys are considered potential candidates as photoelectrodes for photoelectrochemical water splitting. Here we show an In0.25Ga0.75N layer activated by indium nitride quantum dots as efficient photoanode for photoelectrochemical hydrogen generation by water splitting when directly grown on cheap silicon (111) substrates. Photocurrent measurements show more than five times enhancement by the indium nitride quantum dots compared to a bare In0.25Ga0.75N-on-silicon photoanode. The maximum incident photon-to-current conversion efficiency is 44% at 550 nm at 0.4 V, the applied-bias photon-to-current efficiency is 4.1% and the hydrogen and oxygen generation rates are 75 µmol h−1 cm−2 and 33 µmol h−1 cm−2 at 0.2 V under 100 mW cm−2 white light illumination.