First-principles study on GeC/β-AsP heterostructure with type-II band alignment for photocatalytic water splitting

Based on first-principles calculations, the stacking, electronic and optical properties of GeC/β-AsP heterostructure have been explored. It is found that the GeC/β-AsP heterostructure has a direct band gap of 1.28 eV with a type-II band arrangement. Moreover, it is found that the charge density states with the maximum valence band and the minimum conduction band are located in different layers. Thus, the electron-hole pair is spatially separated, which is helpful for improving the photocatalytic performance. In ultraviolet and visible light regions, high optical absorption in an order of 106 cm−1 is found in GeC/β-AsP heterostructure, which is higher than that in its corresponding component monolayers. Considering the potential application of hydrogen reduction and oxygen oxidation, it is found that GeC/β-AsP heterostructure can be used for photocatalytic water cracking.