Direct Chemical Vapor Deposition and On-Site Characterizations of Emergent Two-Dimensional Transition Metal Dichalcogenides on Au Substrates

In recent years, two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted worldwide investigations due to their unique atomic structures, rich physical properties, and promising applications in next-generation electronics/optoelectronics. For the direct syntheses of high-quality 2D TMDCs, chemical vapor deposition (CVD) is widely used because of its excellent controllability over the domain size, thickness, morphology, etc., and scalability with reasonable cost among various synthetic methods. In these efforts, the Au substrates, including polycrystalline foils and single-crystal films, have been carefully selected as ideal templates owing to their chemical inertness, compatibility with on-site characterizations, and strong interfacial couplings with adlayers that facilitate the epitaxy of TMDCs. Hereby, this review summarizes the recent progress in the direct CVD growth of emergent 2D TMDCs on Au substrates, including the syntheses of monolayer TMDCs single crystals on Au single-crystal substrates, as well as their applications in electrocatalytic hydrogen evolution reaction and molecules detection. Meanwhile, this review also reviews the on-site characterizations of TMDCs/Au systems in atomic structures and electronic properties, with particular attention to their epitaxy mechanisms. Finally, challenges and prospects in substrate engineering, more growth strategies and enhanced growth controllability, further developments of characterization techniques, and effective transfer are provided.