Insight into the band structure engineering of single-layer SnS2 with in-plane biaxial strain

Abstract

The effects of in-plane biaxial strain on the electronic structure of a photofunctional material, single-layer SnS₂, were systematically investigated using hybrid density functional calculations. The bonding diagram for the band gap was firstly proposed based on the crystal orbital overlap population analysis. The conduction band-edge of single-layer SnS₂ is determined by the anti-bonding interaction between Sn-5s and S-3p orbitals, while the valence band-edge comes from the anti-bonding between the neighboring S atoms. It is found that the compressive strain not only decreases the indirect band gap of single-layer SnS₂, but also effectively promotes the band-edges of the conduction band to realize the overall water splitting. Besides, the dispersion of the valence band of single-layer SnS₂ becomes weaker with increasing tensile strain which is beneficial for the photo-excitation through direct transitions.