Significantly enhanced performance of an InGaN/GaN nanostructure based photo-electrode for solar power hydrogen generation

A significant reduction in photo-electrochemical etching effects has been achieved on an InGaN/GaN nanorod array structure used as a photoelectrode in NaOH electrolyte by means of depositing transparent nickel oxide nano-particles on the nanorod array structure. Alongside this, the addition of the nickel oxide nano-particles has also led to an increase in photocurrent, thus, enhancing energy conversion efficiency. The enhanced performance is attributed to the discontinuities in both conduction band and valence band formed between the nickel oxide and the GaN, which promote the photo-generated electrons to move to a counter electrode and also lead to an enhanced diffusion of the photo-generated holes from the GaN into the NiO. This effect reduces the recombination of the electrons and the holes due to an increased separation between them and also significantly decreases the photo-electrochemical etching as a result of a sizeable reduction in the number of the photo-generated holes accumulated at the GaN/electrolyte interface.