Based on first-principles calculations, we investigate in detail the structural stability and electron-optical properties of monolayer PtSe₂, HfS₂, and two-dimensional (2D) PtSe₂/HfS₂ van der Waals (vdW) heterostructure. The results show that 0.57eV indirect bandgap semiconductor and Type-II band alignment are formed at the PtSe₂/HfS₂ vdW heterostructure, which greatly promotes the effective separation of photogenerated electrons and holes. It is worth mentioning that the heterostructure exhibits a wider light absorption range and a higher light absorption intensity. The band structure of the heterostructure can be changed significantly by applying an applied electric field, but the Type-II band alignment remains all the time, and the transition from semiconductor to metal occurs when the critical electric field is reached. In addition, the PtSe₂/HfS₂ heterostructure changes from Type-II to Type-I band alignment under different biaxial strains, while the heterostructure keeps the Type-II band alignment under uniaxial strains, and changes from semiconductor to metal with the increase of strain. It is worth noting that the heterostructure is sensitive to compressive strain but insensitive to tensile strain, which provides theoretical guidance for photoelectric devices in specific environments. These results indicate that PtSe₂/HfS₂ heterostructure will be widely used in photodetectors and nanodevices.

基于第一性原理计算，我们详细研究了单层PtSe ₂、 HfS ₂和二维（2D）PtSe ₂ / HfS ₂范德华（vdW）异质结构的结构稳定性和电子光学特性。结果表明，在PtSe ₂ / HfS _{2处形成了0.57eV的间接带隙半导体和Type-II能带排列。}vdW异质结构，极大地促进了光生电子和空穴的有效分离。值得一提的是，异质结构具有更宽的光吸收范围和更高的光吸收强度。异质结构的能带结构可以通过施加电场来显着改变，但 II 型能带排列始终保持不变，当达到临界电场时会发生从半导体到金属的转变。此外，PtSe ₂ / HfS ₂异质结构在不同的双轴应变下从Type-II变为Type-I带排列，而异质结构在单轴应变下保持Type-II带排列, 并随着应变的增加从半导体变为金属。值得注意的是，异质结构对压应变敏感但对拉应变不敏感，这为光电器件在特定环境下提供了理论指导。这些结果表明PtSe ₂ / _{HfS 2}异质结构将广泛用于光电探测器和纳米器件。