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

Van der Waals heterostructures have attracted widespread attention due to their unique photoelectric properties. In this study, the MoTe2/BP vdWH's formation and stability, electrical structure, and optical properties are examined utilizing density functional theory (DFT) calculations. Using the PBE and HSE06 methods, it is discovered that the type of band alignment in the heterojunction is type-I, and it has indirect bandgap 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 type of 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 type-I to type-II band alignment and semiconductor-metal transitions. With the interlayer spacing increasing and tensile stress applied, 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 insightful theoretical direction for prospective uses of novel 2D van der Waals heterostructures in various fields, including solar cells and photodetectors.