Tuning the electronic and optical properties of Type-I PbI2/α-tellurene van der Waals heterostructure via biaxial strain and external electric field

Abstract

Using density functional theory (DFT), we systematically studied the impact of biaxial strain and an external electric field on the electronic and optical properties of two-dimensional PbI2/α-Te van der Waals (vdW) heterostructures. The stability of the constructed PbI2/α-Te heterostructures has been predicted based on the binding energy, phonon spectrum, and molecular dynamics simulation. Our results have revealed that the most stable PbI2/α-Te vdW heterostructure has a distinct type-I band alignment with an indirect bandgap of 0.64 eV. The intrinsic type-I band alignment can be transformed to either type-II or type-III by applying a strong external electric field, which holds great potential for designing multifunctional devices. Furthermore, the compressive and tensile strains can be varied to effectively tune the bandgap value between 0.55 eV and 0.85 eV. Additionally, the constructed PbI2/α-Te vdW heterostructure exhibits excellent optical absorption properties in the UV–Vis regions under biaxial strain and external electric field. Overall, the constructed PbI2/α-Te heterostructure is expected to find potential applications in nanoelectronic devices.