Enhancement electronic and optical properties of two-dimensional ZnSe monolayer via adsorption with SO2, CO and CO2 molecules

To study the electrical and optical characteristics of adsorbed SO2, CO, and CO2 molecules on ZnSe monolayer, first-principles calculations were performed. Our results show that adsorption affects the energy gap of ZnSe monolayer (1.74 eV) between 0.760 and 1.741 eV. The physisorption of SO2 molecules is also thought to occur. Thus, ZnSe monolayer cannot detect these compounds. The reduced adsorption energy of CO and CO2 molecules on ZnSe monolayer makes it unsuitable as a gas sensor. ZnSe monolayer is better suitable for SO2 sensors due to its strong SO2 binding. We also hypothesise that ZnSe monolayer can sensitively monitor SO2 sensors with moderate adsorption energy. In the UV, adsorbed CO and CO2 on ZnSe monolayer have greater loss function and reflectivity than other molecules. The light absorption of gas adsorbed on ZnSe monolayer has been greatly improved. Adsorption of molecules can change the electrical and optical characteristics of ZnSe monolayer, according to this study.