Oxygen and hydroxyl adsorption on MS2 (M = Mo,W, Hf) monolayers: a first‐principles molecular dynamics study

In this paper, we study the oxygen and hydroxyl adsorption on both pristine and S deficient MS₂ (M = Mo, W, Hf) monolayers, using first‐principles molecular dynamics calculations. Our simulations reveal that single‐layer HfS₂ suffers severely from oxidation, which results in the formation of strong Hf–O bonds, likely degrading the transport properties of the material. Oxygen adsorption on S deficient monolayers acts as a passivation mechanism, both ”structurally” by saturating the dangling bonds of neighboring metal atoms and ”electronically” by removing the S vacancy induced gap states. Hydroxyl adsorption on pristine monolayers generates spin‐polarized gap states, and for HfS₂ in particular, causes the Fermi level pinning close to the conduction band edge.