First-principles study of the electronic structure and optical properties of the InSe/ZrSSe heterostructure

Abstract Based on the excellent physical properties of the two-dimensional materials InSe and ZrSSe, exploring whether their heterostructures can realize tunable band alignment has become an important scientific issue in the research of optoelectronic functional materials. In this work, first-principles calculations based on density functional theory (DFT) were employed to systematically investigate the evolution of the electronic structure and optical properties of InSe/ZrSSe van der Waals heterostructures (vdW heterostructures) under varying interlayer distances, strain, and external electric fields. The results show that both the InSe/SeZrS and InSe/SZrSe heterostructures exhibit type-II band alignment, enabling efficient interfacial separation of photoinduced electron–hole pairs and delivering excellent optical absorption from the visible to the near-infrared region. Notably, for the InSe/SZrSe heterostructure, both the conduction-band minimum (CBM) and valence-band maximum (VBM) shift regularly under either uniaxial or biaxial strain, when the strain exceeds 3%, the band alignment can transform from type II to type I. Moreover, under an applied out-of-plane electric field, heterostructure model can undergo transitions from type II to type I or even type III band alignment. These findings highlight the broad application potential of InSe/ZrSSe heterostructures in photocatalysis and optoelectronic devices, and provide a solid theoretical basis for their experimental fabrication and device design.