Water Promotion on Chemical Vapor Deposited Large Area 2D MoS₂

High quality and large area growth of mono-layered MoS₂ is desired with good experimental repeatability and reproducibility. However, this is still a challenge to experimentalists. In this talk, I will present results of 2D MoS₂ growth by chemical vapor deposition (CVD) using water as a promoter. It was found that water droplets have a promotion and stabilization effect on the growth of triangle-shape-flakes of 2-D MoS₂ and continuous films of monolayer and multilayer. By varying the quantity and distribution of water on the growth substrate, it was possible to tune the size and number of layers of MoS₂, the areal coverage of MoS₂, and the distribution area to stacking direction. The results showed good experimental repeatability and reproducibility. Raman microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the layer number, island size, distribution and crystallinity based on optical images from optical microscopy. This study demonstrates the controllability on 2D MoS₂ growth with a simple setup of water assistance and paves a new way for synthesizing large areas of 2D MoS₂ through a simplified growth process that improves controllability and experimental repeatability and reproducibility.