Direct Growth of MoS 2 and WS 2 Layers by Metal Organic Chemical Vapor Deposition

For the growth of 2D transition metal dichalcogenides, such as molybdenum (MoS 2 ) and tungsten disulfides (WS 2 ), 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 MoS 2 and WS 2 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‐MoS 2 and 2H‐WS 2 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.