H_(2)S-assisted growth of 2D MS_(2)(M=Ti,Zr,Nb)

2D transition metal dichalcogenides (TMDCs) have drawn an enormous amount of attention due to their fascinating properties and application potential in next-generation information process and storage. However, the lack of proper synthesis approach limits their application. Here, we report a controllable synthesis method to grow ultrathin MS2 (M = Ti, Nb, Zr) nanosheets with H_(2)S-assisted chemical vapor deposition (CVD). We found that the presence of H_(2)S plays an important role to control the morphology of nanosheets including the lateral size and the nucleation density. With the assistance of H_(2)S, the growth of MS2 shows much thinner thickness with largely decreased nucleation density, beneficial for the device application, which can be attributed to the kinetics dominated growth. Our method hence opens a new avenue for the CVD growth of 2D TMDCs and the corresponding heterojunction, and paves the way for exploring their intriguing properties and applications.