Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted great research interests due to their potential applications in electronics, photonics, optoelectronics, etc. Chemical vapor deposition (CVD) technique is believed to be the most promising method to realize the batch production of high-quality 2D TMDCs. However, precise control of TMDCs’ growth and properties by the CVD method is still a challenge. In this thesis, several strategies are provided for manipulating the CVD growth process and engineering the structures of 2D TMDCs. Firstly, the monolayer MoS₂ with pointed star-like morphologies have been successfully prepared via the CVD method. Theoretical calculations imply the defects density is closely related to the sample morphology. By pretreating t...[ Read more ]

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted great research interests due to their potential applications in electronics, photonics, optoelectronics, etc. Chemical vapor deposition (CVD) technique is believed to be the most promising method to realize the batch production of high-quality 2D TMDCs. However, precise control of TMDCs’ growth and properties by the CVD method is still a challenge. In this thesis, several strategies are provided for manipulating the CVD growth process and engineering the structures of 2D TMDCs. Firstly, the monolayer MoS₂ with pointed star-like morphologies have been successfully prepared via the CVD method. Theoretical calculations imply the defects density is closely related to the sample morphology. By pretreating the growth substrate with adhesive seeds, the dendritic MoS₂ with hexagonal backbones have been controllably synthesized. These MoS₂ dendrites consist of massive twin defects which greatly enhance the photoluminescence (PL) emission. Moreover, by using the m-plane single-crystal quartz as the growth substrate, aligned growth of monolayer WS₂ together with the engineered band structure and dimension have been achieved. A direct-indirect bandgap transition of monolayer WS₂ occurs when the substrate is cooled down to the low temperature. By controlling the growth time, the dimension of epitaxial WS₂ can be tailored from the 2D triangle to the one-dimensional ribbon. Finally, wrinkled WS₂ arrays have been directly prepared on m-plain quartz by a simple post-quenching process. These nanoscale WS₂ wrinkles exhibit anisotropic Raman response, patterned PL emission, and enhanced chemical reactivity.