Wafer-scale synthesis of thickness-controllable MoS2 films via solution-processing using a dimethylformamide/n-butylamine/2-aminoethanol solvent system.

The wafer-scale synthesis of two-dimensional molybdenum disulfide (MoS2) films, with high layer-controllability and uniformity, remains a significant challenge in the fields of nano and optoelectronics. Here, we report the highly thickness controllable growth of uniform MoS2 thin films on the wafer-scale via a spin-coating route. Formulation of a dimethylformamide-based MoS2 precursor solution mixed with additional amine- and amino alcohol-based solvents (n-butylamine and 2-aminoethanol) allowed for the formation of a uniform coating of MoS2 thin films over a 2 inch wafer-scale SiO2/Si substrate. In addition, facile control of the average number of stacking layers is demonstrated by simply manipulating the concentration of the precursor solution. Various characterization results reveal that the synthesized MoS2 film has wafer-scale homogeneity with excellent crystalline quality and a stoichiometric chemical composition. To further demonstrate possible device applications, a mostly penta-layered MoS2 thin film was integrated into a top-gated field-effect transistor as the channel layer and we also successfully transferred our films onto transparent/flexible substrates.