Phosphorene as H2S and CH4 Gas Sensor

Abstract

First-principle calculations within density functional theory are carried out to investigate the adsorption of various gas molecules, including hydrogen sulfide and methane on two-dimensional monolayer phosphorene in order to fully exploit the gas sensing capabilities. The adsorption properties of different molecules in the environment on monolayer phosphorene base material is discussed in terms of the Mulliken charge transfer, energy band gap, adsorption energy. The prominent adsorption sites of methane, hydrogen sulfide, water, and oxygen on monolayer phosphorene are investigated at an atomistic level. Based on the results the transport properties of monolayer phosphorene exposed to these gas molecules are investigated both in zigzag and armchair direction using non-equilibrium Green function tuned with density functional theory. The results show that using both directions simultaneously as gas sensing can be an effective technique to distinguish hydrogen sulfide and methane gas molecules from others and demonstrate great selectivity.