Adsorption and gas-sensing performance of SF6 decomposition gases on GeS monolayers with and without single vacancies and Si-doping

Abstract

First principles calculations were performed to systematically study the structural and electronic properties of SF6 decomposition gases (SO2, HF, H2S, SOF2 and SO2F2) adsorbed on the GeS monolayer with and without single vacancies and Si-doping. We found that the pristine GeS monolayer as work function (Φ) type gas sensors for detecting SO2 and HF gases has high sensitivity and selectivity. Due to the remarkable changes of band structures and density of states after molecular adsorption, the GeS monolayer with Ge vacancy (VGe-GeS) could be high-performance gas sensors for detecting SO2, HF, and SOF2 gases at room temperature, and a good candidate for H2S detection at high temperature. Further, the VGe-GeS monolayer is a promising potential for Φ-type gas sensors for SO2 detection. The GeS monolayer with S vacancy has high potential as a Φ-type SOF2 gas sensor at room temperature. The GeS monolayer with S substituted by Si is a room-temperature high-performance gas sensor for detecting SOF2 gas because of its obvious modification of electronic properties of monolayers, and a Φ-type gas sensor for H2S detection. However, the GeS monolayer with Ge substituted by Si can be viewed as Φ-type gas sensors for SO2, HF, and SOF2 detection.