A First-Principles Study on the Adsorption of Small Molecules on Arsenene: Comparison of Oxidation Kinetics in Arsenene,Antimonene, Phosphorene,and InSe

Arsenene, a new group-V two-dimensional (2D) semiconducting material beyond phosphorene and antimonene, has recently gained an increasing attention owning to its various interesting properties which can be altered or intentionally functionalized by chemical reactions with various molecules. This work provides a systematic study on the interactions of arsenene with the small molecules, including H₂, NH₃, O₂, H₂O, NO, and NO₂. It is predicted that O₂, H₂O, NO, and NO₂ are strong acceptors, while NH₃ serves as a donor. Importantly, it is shown a negligible charge transfer between H₂ and arsenene which is ten times lower than that between H₂ and phosphorene and about thousand times lower than that between H₂ and InSe and antimonene. The calculated energy barrier for O₂ splitting on arsenene is found to be as low as 0.67 eV. Thus, pristine arsenene may easily oxidize in ambient conditions as other group V 2D materials. On the other hand, the acceptor role of H₂O on arsenene, similarly to the cases of antimonene and InSe, may help to prevent the proton transfer between H₂O and O− species by forming acids, which suppresses further structural degradation of arsenene. The structural decomposition of the 2D layers upon interaction with the environment may be avoided due to the acceptor role of H₂O molecules as the study predicts from the comparison of common group V 2D materials. However, the protection for arsenene is still required due to its strong interaction with other small environmental molecules. The present work renders the possible ways to protect arsenene from structure degradation and to modulate its electronic properties, which is useful for the material synthesis, storage and applications.