Evolution of transition metal dichalcogenide film properties during chemical vapor deposition: from monolayer islands to nanowalls.

Unique properties possessed by transition metal dichalcogenides (TMDs) attract much attention in terms of investigation of their formation and dependence of their characteristics on the production process parameters. Here, we investigate the formation of TMD films during chemical vapor deposition (CVD) in a mixture of thermally activated gaseous HS and vaporized transition metals. Our observations of changes in morphology, Raman spectra, and photoluminescence (PL) properties in combination withmeasurements of the electrical conductivity of the deposits formed at various precursor concentrations and CVD durations are evidence of existence of particular stages in the TMD material formation.