Investigation of two-dimensional HfS2/PtSSe heterostructure with strong visible light adsorption and strain tunable bandgap

Abstract

Abstract Based on the first-principles calculation, the electronic structure of HfS2/PtSSe heterojunction is systematically studied. The HfS2/PtSSe heterostructure has an intrinsic type-II band alignment, with holes and electrons located at HfS2 and PtSSe, respectively. The charge distribution is well separated, which can effectively prevent carrier recombination. Compared to the isolated PtSSe and HfS2 monolayers, the light absorption of the HfS2/PtSSe heterojunction in both visible and ultraviolet regions is significantly enhanced. Furthermore, the bandgap of the heterojunction can be tuned linearly by the bi-axial strain. Especially, the heterojunction can switch from type-II to type-III band alignment at compress strain strength of −9%. The variation of the bandgap of the heterojunction is related to the increased hybridization of Hf-5d and Se-4p states under compressed strain. The adjustable bandgap indicates that the HfS2/PtSSe heterojunction is a promising high-performance adjustable optoelectronic nanodevice candidate.