First-principles study on the strain-modulated structure and electronic properties of janus tin oxide selenide monolayer

Abstract

Using first-principles calculations, the structure and electronic properties of a Janus tin oxide selenide (SnOSe) monolayer under the influence of uniaxial and biaxial strain were investigated. The results revealed that in the absence of strain, the Janus SnOSe monolayer displayed semiconducting properties with a direct band gap of 0.32 eV, as calculated by the HSE06 method. Uniaxial strain along the x-direction led to an indirect-direct band gap transition, while under the impact of uniaxial strain along the y-direction, the material changed from a metal to a direct band gap semiconductor. When the biaxial strain was applied to monolayer SnOSe, a similar transition from a metal to a semiconductor occurred, and the tunable range of the direct band gap significantly increased and could be adjusted from 0 eV to 1.30 eV. It has also been found that under the influence of uniaxial or biaxial tensile strain, monolayer SnOSe remained as a direct band gap semiconductor whose band gap increased upon the increment in tensile strain. Our results also demonstrated that the work function of monolayer SnOSe increased rapidly as the strain changed from −10% to 10%. These findings prove that strain engineering can be employed to tune the electronic properties of the Janus SnOSe monolayer.