Optoelectronic Property Exploration in SnS₂ Monolayer and Homojunctions with Non-metallic Element (B, C, N) Doping: A First-Principles Investigation

The first-principles approach was used to investigate the effect of doping with non-metallic elements (B, C, and N) on the optoelectronic properties of 1T-SnS₂ monolayers and homojunction. We discussed the changes in geometry, energy band structure, complex dielectric function, absorption properties, and reflection coefficients. The calculation results of formation energy indicate that the N-doped system has a minor formation energy of –1.452 and –1.023 eV in the monolayer and homojunction, respectively, which suggests that N-doping is the easiest to realize. In the monolayer structure, B-doping leads to the transition from semiconductor to metal system, while C-doping and N-doping result in the narrowing of the band gap. In the bilayer structure, B-doping and N-doping turn the system into metallicity, while C-doping eventuates more significant band gap reduction. In addition, the results of optical properties show that N-doping has a more significant effect on increasing the reflectivity of SnS₂ monolayer and homogeneous structures compared to B and C doping. These findings help us better understand the effect of non-metallic element doping on SnS₂ and provide an essential theoretical reference for the potential application of SnS₂ in microelectronic devices, which is of practical significance for material design and performance improvement.