Surface enhanced Raman effect on CVD growth of WS2 film

Abstract Chemical vapor deposition (CVD) method was used to grow large area and layer controllable WS2 film. Our results show that the as grown WS2 film is an excellent substrate for surface enhanced Raman scattering (SERS). The Raman enhancement effect depends crucially on the layer number of WS2 film: monolayer WS2 offers the strongest Raman signal, and the Raman enhancement effect gradually decreases with the increase in the layer number of WS2. Further analysis indicates that this transition originates from the charge transfer yield between the R6G molecules and the underlying WS2 substrate.