The fabrication and tunable optical properties of 2D transition metal dichalcogenides heterostructures by adjusting the thickness of Mo/W films

Feasible strategy developed to realize the fabrication of two-dimensional (2D) transition-metal dichalcogenides (TMDCs) vertical/lateral heterostructures is highly desirable and beneficial for the construction of ultrathin and novel optoelectronic devices. In this work, we report the fabrication of diverse 2D TMDCs structures, such as MoS2 monolayer, WS2 monolayer, Mo1-xWxS2 alloy, and WS2-Mo1-xWxS2 lateral/vertical heterostructure, through one-step chemical vapor deposition (CVD) approach via adjusting stacking sequence and thickness of Mo/W films. Systematical Raman and PL characterizations have elucidated that the obtained samples are 2H phase, and possess outstanding structural and optical modulations. The possible growth mechanism of the 2D TMDC crystals with versatile structures has been discussed based on adjustable vapor pressure and interdiffusion of Mo/W atoms. Our experiments confirm the possibility of the synthesis strategy to promote the progress of different 2D-TMDC-based structures, benefiting for various optoelectronic applications.