Progress in the chemical vapor deposition of 2D transition metal dichalcogenides: toward structural and morphological engineering

Transition metal dichalcogenides (TMDs) have emerged as a versatile class of 2D materials owing to their unique structural characteristics and diverse electronic properties. Depending on their composition, crystallographic phase, and stacking order, TMDs exhibit metallic, semiconducting, or insulating behaviour. While this opens up a wide spectrum of applications, it also poses considerable challenges in their synthesis. Chemical vapor deposition (CVD), an already well-established technology in the semiconducting manufacturing, is the most promising route for the large-scale synthesis of TMDs. This review provides an overview of the CVD synthesis of TMDs, with special emphasis on phase engineering, large-area growth, and heterostructure fabrication. Two important domains of large area synthesis, namely epitaxial growth and salt-assisted synthesis, are explored in depth. The review concludes by highlighting existing knowledge gaps and challenges, and proposes future research directions in this rapidly evolving field.