Photoluminescence Enhancement Effect of the Layered MoS2 Film Grown by CVD

The layered MoS2 films have been prepared by the chemical vapor deposition (CVD) method, which shows numerous MoS2 convex flakes (i.e., MoS2 nanosheets) on SiO2/Si substrates. The convex flake islands form a uniform layered film and the single flake corresponds to one small piece of monolayer MoS2 film; they show a strong photoluminescence (PL) radiation as a whole. The thickness of the layered MoS2 films increases with the increases of growth time, the effect of diverse growth time on the properties of layered MoS2 films has been discussed, and the PL enhancement effect is due to the PL intensity accumulation from each of the convex flakes. The strong PL radiation has been found by annealing the samples and the reason has been analyzed. The layered MoS2 films could provide more photon energy than both the monolayer MoS2 film and the bulk MoS2. This work provides a fundamental study about the device fabrication based on layered MoS2 films. The optoelectronic devices based on this study will be more energy efficient.