Adsorption of gas molecules on graphene-like InN monolayer: A first-principle study

Highlights: • A comprehensive adsorption mechanism of InN monolayer is theoretical studied to distinguish the physic/chemi-sorption. • Different adsorption sites for different gases are systematically discussed. • The influence (enhanced or weakened) of external electric field to InN-gas system is well investigated. • The influences of gas adsorption to the optical properties (work function and light adsorption ability) of InN monolayer are also researched. - Abstract: Using first-principles calculation within density functional theory (DFT), we study the gas (CO, NH₃, H₂S, NO₂, NO, SO₂) adsorption properties on the surface of single-layer indium nitride (InN). Four different adsorption sites (Bridge, In, N, Hollow) are chosen to explore the most sensitive adsorption site. On the basis of the adsorption energy, band gap and charge transfer, we find that the most energetic favourable site is changeable between In site and N site for different gases. Moreover, our results reveal that InN is sensitive to NH₃, SO₂, H₂S and NO₂, by a physisorption or a chemisorption nature. We also perform a perpendicular electric field to the system and find that the applied electric field has a significant effect for the adsorption process. Besides, we also observed the desorption effects on NH₃ adsorbed at the hollow site of InN when the electric field applied. In addition, the optical properties of InN monolayer affected by different gases are also discussed. Most of the gas adsorptions will cause the inhibition of light adsorption while the others can reduce the work function or enhance the adsorption ability in visible region. Our theoretical results indicate that monolayer InN is a promising candidate for gas sensing applications.