Theoretical study on the electronic structure, optical and photocatalytic properties of type-II As/CdO van der Waals heterostructure

Recently, van der Waals (vdW) heterostructures have attracted extensive research interest due to their extraordinary properties and potential applications in photovoltaic and photocatalytic devices. Here, we propose As/CdO vdW heterostructure with compelling optical and photocatalytic properties which has been studied by means of first-principles calculations. The stability of the heterostructure is verified by calculating the binding energy and ab-initio molecular dynamics simulations. We demonstrate that the As/CdO vdW heterostructure possesses a direct band gap of about 1.96 eV with type-II (staggered) band alignment, which can effectively reduce the recombination of photogenerated electron-hole pairs. Compared with two isolated parts, As/CdO vdW heterostructure shows suitable band edge positions and high absorption efficiency in the visible and ultraviolet light regions, making it a good candidate for optical devices and photocatalytic water splitting. The calculated higher carrier mobility of holes and electrons along the armchair direction are 932.510 cm2 V-1 s- 1 and 90.808 cm2 V-1 s- 1, respectively. Biaxial strain can modulate the electronic structure and optical characteristics of As/ CdO vdW heterostructure. In particular, compressive strain shows robust type-II band alignment and improve the optical performance of As/CdO vdW heterostructure in the visible light region. Our results are beneficial for designing optoelectronic and photocatalytic devices.