A nitride based polarization-engineered photocathode for water splitting without a p-type semiconductor

Photoelectrochemical water splitting is a promising way for hydrogen production with low environmental burden. Although III-nitride semiconductors have potentially favorable properties as water splitting photoelectrodes, they have several limitations for practical use currently. In this study, the concept of a polarization-engineered nitride photocathode for water splitting is proposed to overcome this problem. We observed that the proposed GaN/AlN/GaN structure worked as a photocathode even though it consisted of only n-type III-nitride semiconductors. This polarization-engineered photocathode showed a remarkably stable and relatively high photocurrent since it can avoid the causes of problems from which both n-type and p-type conventional GaN photoelectrodes suffer.