Direct observation of nucleation dynamics for atomically thin layered 2D semiconductor material

Abstract

Transition metal dichalcogenides (TMDs) are atomically thin layered materials that have attracted intense attention because of their outstanding optical and electrical properties. Despite recent advances in production, the quality of TMD crystals still requires improvement. Elucidating details of the TMD crystal-growth mechanism is therefore critically important. To this end, we have developed a technique for in-situ monitoring of chemical vapor deposition, allowing direct and detailed observation of the crystal nucleation and growth dynamics of monolayer and single-crystal TMD. Here, we review our recent experimental and theoretical findings about the TMD growth mechanism, including the diffusion length of precursors, non-classical nucleation, and liquid–solid-transfer growth.