Band structure engineering in a MoS2/PbI2 van der Waals heterostructure via an external electric field
Abstract
Band structure engineering in a MoS2/PbI2 van der Waals (vdW) heterostructure under an external electric field (Efield) is investigated using density functional theory (DFT). It is demonstrated that the MoS2/PbI2 vdW heterostructure has a type-II heterojunction with a direct bandgap, and thus the lowest energy electron–hole pairs are spatially separated. Meanwhile, the band structure could be effectively modulated under an Efield and the bandgap shows linear variations with the Efield, indicating a giant Stark effect. This gets further support from the band edges of MoS2 and PbI2 in the heterostructure. Moreover, the MoS2/PbI2 vdW heterostructure experiences transitions from type-II to type-I and then to type-II under various Efields. Our calculated results pave the way for experimental research and provide a new perspective for the application of the vdW heterostructure in electronic and optoelectronic devices.