Highly Sensitive and Selective Gas Detection Based on Silicene

Abstract

Recent advances in the fabrication of silicene devices have raised exciting prospects for practical applications such as gas sensing. We investigated the gas detection performance of silicene nanosensors for four different gases (NO, NO₂, NH₃, and CO) in terms of sensitivity and selectivity, employing density functional theory and nonequilibrium Green’s function method. The structural configurations, adsorption sites, binding energies and charge transfer of all studied gas molecules on silicene nanosensors are systematically discussed in this work. Our results indicate that pristine silicene exhibits strong sensitivity for NO and NO₂, while it appears incapable of sensing CO and NH₃. In an attempt to overcome sensitivity limitations due to weak van der Waals interaction of those latter gas molecules on the device, we doped pristine silicene with either B or N atoms, leading to enhanced binding energy as well as charge transfer, and subsequently a significant improvement of sensitivity. A distinction between the four studied gases based on the silicene devices appears possible, and thus these promise to be next-generation nanosensors for highly sensitive and selective gas detection