2D Bi OSe Based Highly Selective and Sensitive Toxic Non-Condensable Gas Sensor

In this study, we discussed the interaction of toxic NCG with monolayer (ML) Bismuth Oxyselenide (Bi_{2}O_{2}Se) for the first time. The density functional theory (DFT) combined with non equilibrium Green's function (NEGF) were used to investigate gas sensing properties of ML Bi_{2}O_{2}Se with and without Se vacancy. The authors discussed adsorption energy, adsorption sites, charge exchange, band structure, density of states (DOS), and current-voltage properties with adsorbed toxic Non-condensable gases (NO_{2}, NO, NH_{3}, CO, and CO_{2}). Our study indicates that NO_{2} has the lowest adsorption energy and highest charge transfer that results in superior NO_{2} selectivity of vacancy less (VL) Bi_{2}O_{2}Se. The band structure and DOS analysis show that adsorption of only NO_{2} and NO results in the addition of impurity states near the Fermi level in VL Bi_{2}O_{2}Se. The presence of Se vacancy (SV) can further improve the sensitivity and selectivity of Bi_{2}O_{2}Se towards sensing toxic gases when compared with VL Bi_{2}O_{2}Se. It was found that SV Bi_{2}O_{2}