Adsorption and optical properties of H2S, CH4, NO, and SO2 gas molecules on arsenene: a DFT study

The adsorption and optical properties of H2S, CH4, NO, and SO2 gas molecules onto arsenene is investigated by density functional theory. The NO gas molecule significantly modifies the band structure and density of states near the Fermi level, which suggests that arsenene is more sensitive to this gas molecule. The results indicate that arsenene exhibits weak sensitivity to H2S and CH4 molecules. The current–voltage (I–V) characteristics before and after gas exposure are calculated using the nonequilibrium Green’s function formalism. The I–V characteristics of the sensor demonstrate high sensitivity to NO gas molecules. Moreover, the current passing through arsenene is remarkably improved after SO2 adsorption under a bias voltage of 2.8 V. In addition, exposure to NO and SO2 gas molecules modifies the optical spectrum of arsenene. Therefore, arsenene could be a promising candidate for NO and SO2 optical gas sensors.