Electronic structure and optical properties of InSe/α-AsP van der Waals heterostructure from DFT calculations

Abstract The electro-optical properties of Indium Selenide/Black Arsenic Phosphorus (InSe/α-AsP) van der Waals heterojunction have been systematically investigated by using first-principles calculations. The presented two-dimensional (2D) heterojunction possesses a narrow direct bandgap (1.07 eV), with a high absorption coefficient in the infrared region and a cutoff wavelength of ~2 μm. Type-II band alignment is predicted which would lead to an efficient separation of electrons and holes. Charge carrier mobilities are calculated reaching up to 103 cm2V−1s−1 at room-temperature, which promises high-performance electron transport behavior. Lattice strain is revealed to tune the band structure but without changing the type-II band alignment of the InSe/α-AsP van der Waals heterojunction. These results suggest that InSe/α-AsP van der Waals heterojunction is a promising candidate for infrared photodetection devices.