Oxidation dynamics: A Molecular Dynamics Study*

Understanding oxidation mechanisms of layered semiconducting transition-metal dichalcogenide (TMDC) plays an important role in controlling the formation of native oxide as well as in synthesis of oxide and oxysulfide products. Here, we perform reactive molecular dynamics simulations with optimized reactive force field and show the influence of oxygen partial pressure on not only the ZrS₂ oxidation rate but also the oxide morphology and quality. As the oxidation progresses, we observe a transition from an oxidation process occurring layer-by-layer to a continuous oxidation mediated by amorphous oxide. We present that different pressure levels selectively reveal distinct oxidation stages within a specific simulation time frame. The conventional Deal-Grove model describes the kinetics of the fast continuous oxidation stage well, while reactive bond-switching mechanisms governs the layer-by-layer oxidation stage. This research provides atomistic insights for the oxidation mechanisms of ZrS₂ and offers a potential foundation for controlled oxidation of a wide range of TMDC materials through the manipulation of pressure.