Direct Growth of MoS2 and WS2 Layers by Metal Organic Chemical Vapor Deposition

For the growth of 2D transition metal dichalcogenides, such as molybdenum (MoS2) and tungsten disulfides (WS2), metalorganic chemical vapor deposition (MOCVD) routes are favorable due to their superior scalability, the possibility to tune the processing temperatures by a proper choice of reactants thus avoiding the need for a postdeposition treatment. Herein, the first example of a promising MOCVD route for the direct fabrication of MoS2 and WS2 layers under moderate process conditions is reported. This straightforward route is successfully realized by the combination of metalorganic precursors of Mo or W bearing the amidinato ligand with just elemental sulfur. The formation of stoichiometric hexagonal 2H-MoS2 and 2H-WS2 is demonstrated which is confirmed by Raman, X-ray diffraction, and X-ray photoelectron spectroscopy studies. The deposited layers are evaluated for their electrocatalytic activity in hydrogen evolution reaction as a proof of principle for application in water splitting devices.