Study on the electronic structure and optical properties of InSb/WSSe van der Waals heterostructure

Van der Waals heterostructures offer promising avenues for designing optoelectronic materials with tailored functionalities. Here, we employ first-principles calculations to investigate the structure, electronic, and optical properties of a novel InSb/WSSe heterojunction. The optimized structure reveals a stable interlayer spacing of 3.229 Å and exhibits type-II band alignment with a direct bandgap of 0.54 eV. Charge density analyses indicate electron transfer from the InSb layer to WSSe, resulting in an intrinsic interfacial electric field directed from InSb to WSSe. The heterojunction features a work function of 5.12 eV and demonstrates a notable enhancement of 37%. The InSb/WSSe heterojunction effectively combines the optical advantages of its constituent materials. Optical absorption is significantly boosted across the infrared, visible, and near-ultraviolet regions, with peak absorption in the visible spectrum reaching 20.63%—representing 44% increase than the monolayer components. In the infrared region, the absorption rate of the heterojunction breaks through from 0 to 14.96%. In the near-ultraviolet region, absorption improves by 26.6% compared to monolayer WSSe. Moreover, compared to monolayer WSSe, the heterostructure effectively suppresses optical transmittance (84.36%) and exhibits distinctive reflectance peaks. These findings highlight the InSb/WSSe heterojunction as a promising platform for broadband light-harvesting and next-generation optoelectronic applications. Graphical abstract