Tunable electronic and optical properties of the MoTe2/black phosphorene van der Waals heterostructure: a first-principles study†

Abstract

van der Waals heterostructures have attracted widespread attention due to their unique photoelectric properties. In this study, formation and stability, electrical structure, and optical properties of the MoTe₂/BP vdWH are examined utilizing density functional theory (DFT) calculations. Using the PBE and HSE06 methods, it has been discovered that the band alignment in the heterojunction is of type-I, and it has indirect bandgaps of 1.01 eV and 1.44 eV, respectively. A weak van der Waals force exists between the MoTe₂ and BP layers. Notably, compared to isolated MoTe₂ and BP monolayers, the heterojunction demonstrates a higher absorption coefficient (∼10⁵ cm⁻¹) and a broader absorption wavelength range. Furthermore, we have shown that the band alignments of the heterojunction can be adjusted by applying biaxial strain, introducing an external electric field, and altering the interlayer spacing. These adjustments enable a type-I to type-II band alignment and semiconductor–metal transitions. With increasing the interlayer spacing and applied tensile stress, the absorption intensity in the UV-vis range gradually decreases. Interestingly, the external electric field shows minimal impact on the absorption intensity. This study offers an insightful theoretical direction for the prospective use of novel 2D van der Waals heterostructures in various fields, including solar cells and photodetectors.