Type-II GeC/ZnTe heterostructure with high-efficiency of photoelectrochemical water splitting

Abstract

Efficient carrier separation and suitable band edge position are necessary conditions for photocatalytic water splitting. Based on density functional theory, the electronic properties and optical performance of the GeC/ZnTe vdW heterostructure are systematically explored. The heterostructure with inherent type-II band arrangement is conducive to constantly separate the hole–electron pairs, thus improving the utilization of solar energy. Meanwhile, an excellent optical absorption coefficient has been proved in the heterostructure with large carrier mobility. Within the strain range of –4% to +3%, the heterostructure possesses appropriate band edges for photocatalytic water splitting and the light absorption performance is obviously improved. High solar-to-hydrogen efficiency (26.81%) means that the heterostructure can effectively convert photon energy into water splitting. These findings predict the possibility of GeC/ZnTe heterostructures as photocatalysts for water splitting and other optoelectronic devices.