ABSTRACT
This chapter discusses the atomic structures, followed by the synthesis and processing, whereas some properties and the applications. The structures or phases present in 2D TMDs are governed by many factors, including the relative stability at different temperatures as well as the synthesis/thermal treatment histories. Selected area electron diffraction shows the crystal structures in reciprocal space, while in transmission electron microscopic, especially scanning transmission electron microscopy images, the spatial and elemental information on a single atomic scale can be directly identified. Then, the exfoliation starts by removing the scotch tape, and repeated mechanical exfoliation eventually achieves monolayer transition metal dichalcogenides (TMDs). The lack of reliable and reproducible synthesis and lack of deep understandings of some fundamental physical and chemical properties originated from their complex and nontrivial electronic structures in 2D TMDs are the most desirable and urgent targets for the whole research societies. A lot of 2D materials are originated from the vdW layered materials, which consist of the stacking of 2D layered building blocks.
