External electric field and strains facilitated nitrogen dioxide gas sensing properties on 2D monolayer and bilayer SnS2 nanosheets

Two-dimensional (2D) nanostructures materials have attracted an exceptional interest in the structural, electronic and optical characteristics due to their ultrathin and flexible nature. Using first-principle simulations, we studied the electronic structures of Nitrogen dioxide adsorbed monolayer and bilayer SnS2 nanosheets. The results demonstrate that Nitrogen dioxide is physisorbed on monolayer and bilayer SnS2 nanosheets acting as acceptors with obvious charge transfer 0.03 e and 0.05 e from the basal to the adsorbate. Moreover, our results show that electric field and biaxial strains can drastically change the adsorption energy, electronic properties and charge transfer of Nitrogen dioxide adsorbed SnS2 systems. Namely, these external conditions are highly preferred and provide a practicable method for adjustable SnS2 based electrical devices and gas sensors. Especially, the giant Stark effect can easily render the NO2-adsorbed SnS2 system from semiconducting to metallic. These distinctive characters endow the SnS2 nanosheets with high sensitivity as a potential candidate for NO2 gas sensor.