Vertical heterojunction photodetector of In2Se3/PtS2 with high polarization sensitivity and tunable electronic characteristics

A monolayer In2Se3 root number model was used with a monolayer PtS2 material 2 x 2 x 1 cell expansion to form an In2Se3/PtS2 bilayer with a lattice mismatch of 3.12 %. Utilizing first principles calculations, we systematically explore the structural, electrical, and optical characteristics of In2Se3/PtS2 heterostructures. The stabilized heterostructure displays an indirect band gap of 1.62 eV and a type I energy band arrangement. Moreover, the absorption spectra further demonstrate the heterostructure's ability to capture visible and UV light, it is significantly better than monolayer In2Se3 and monolayer PtS2, and the absorption peak at a wavelength of 185 nm is as high as 8. 07x105/cm. Using biaxial strain to change the heterojunction energy band structure, it is found that as the biaxial strain field changes, the hetero-structure of In2Se3/PtS2 transforms from a type I to a type II energy band arrangement with the applied stresses of -8 %, 2 %, 4 %, 6 %, and 8 %. Transitioning from simulations to practical applications, we model a novel photodetector based on the In2Se3/PtS2 heterojunction. Remarkably, the In2Se3/PtS2 heterojunction photodetector demonstrates high polarization sensitivity at a photon energy of 3.2 eV, boasting a maximum extinction ratio of 20, outperforming alternatives. In summary, the In2Se3/PtS2 heterostructure presents exceptional optical properties, providing a robust foundation for advanced photodetector applications.