Effects of gas adsorption on monolayer Si₂BN and implications for sensing applications

Using density functional theory, we investigate the adsorption behavior of CO, NH₃, and NO molecules on monolayer Si₂BN. The energetically favorable structural configurations along with their adsorption energies, charge transfers, and electronic properties are discussed. The CO and NH₃molecules show physisorption with moderate adsorption energies, whereas the NO molecule is subject to chemisorption. We further calculate the current-voltage characteristics using the non-equilibrium Green's function formalism. Significant anisotropy is observed for the armchair and zigzag directions, consistent with the anisotropy of the electronic band structure. Pronounced enhancement of the resistivity upon gas adsorption indicates that monolayer Si₂BN is promising as gas sensing material.