Modulation of Gas Adsorption on SnS by strain

Abstract

SnS monolayer has sparked intensive attention due to its unique electronic and optical properties. We systemically investigate the electronic properties of SnS by first-principles calculation. Our results show that the monolayer possesses indirect bandgap. We further perform mechanical strain to adjust the electronic structure of SnS, corresponding results display an indirect-direct transition of band gap when subjected to proper external strain. Interestingly, the bandgap can be linearly increase under tensile strain from 0% to 7%, while the bandgap reduced under compressive strain. For biaxial strain, the band gap changes more remarkable compared with that under uniaxial strain (zigzag x or armchair y direction). Furthermore, we demonstrate that the gas molecules (CO₂, H₂S, C₂H₄ and NO₂) adsorption property on SnS monolayer can be modulated through biaxial strain. Especially, the NO₂ adsorption is further enhanced on the SnS monolayer under biaxial tensile strain. These results may provide guidance for fabricating SnS-based strained gas sensor.