Analysis of the NH3 Adsorption on Boron-Arsenic Co-doped Monolayer Graphene: A First Principle Study

Abstract

Two-dimensional (2D) graphene has drawn significant attention for its potential application in the detection of inorganic gas molecules when doped with appropriate dopants. As of yet, these effects of non-metallic co-doping at the different sub-lattice sites are yet to be observed systematically from a theoretical perspective for gas-molecule detection on graphene. The study investigates molecular adsorption of ammonia (NH3) on boron/arsenic (B/As) monolayer graphene using density functional theory (DFT). In this paper, we evaluate the influence of arsenic impurity on the molecular adsorption of boron-doped graphene in the same and different sub-lattice sites. In the present context, three doping configurations are identified that possess distinct electronic properties and respond characteristically to individual gas molecules. Due to orbital overlaps from the adsorbed gas molecules, molecular adsorption has a considerable impact on the spatial distribution of electronic states along the band edges, resulting in large modulations in the energy bandgaps and effective masses of the co-doped lattices. Co-doping techniques appear to be particularly suitable for electrochemical gas sensing because they result in a significant semiconducting bandgap opening while preserving the inherent nature of graphene. For co-doped lattices, the subsequent molecular adsorptions result in substantial charge transfer between the gas molecules and the host lattice, as well as a significant increase in the density of electronic states around the Fermi level.