DFT computation of two-dimensional CdO/GaS van der Waals heterostructure: Tunable absorption spectra for water splitting application

Based on first-principles calculation, we systematically investigated the electronic structure, charge transfer, and optical properties of the CdO/GaS van der Waals (vdW) heterostructure, and which are effected by applied mechanical strain. Heyd-Scuseria-Ernzerhof (HSE06) is used to accurately calculate the electronic structure, and the results show the CdO/GaS heterostructure is a semiconductor with a direct band gap (1.79 eV), which possess type-II band alignment, and is in favor of the separation of photogenerated carriers and extend their lifetime. The suitable band gap and band edge position of the CdO/GaS heterostructure promise application prospect in photocatalyst for water splitting. The significant advantages of the CdO/GaS heterostructure for photocatalytic performance in whole sunlight spectrum are obtained by applying biaxial strain to the heterostructures.