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.

中文翻译：

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表面增强拉曼效应对WS ₂膜的CVD生长的影响

化学气相沉积（CVD）方法用于生长大面积和可控层的WS ₂膜。我们的结果表明，生长的WS ₂膜是用于表面增强拉曼散射（SERS）的出色基材。拉曼增强效应关键取决于WS ₂膜的层数：单层WS ₂提供最强的拉曼信号，并且拉曼增强效应随着WS ₂层数的增加而逐渐降低。进一步的分析表明，这种转变源自R6G分子与下面的WS ₂底物之间的电荷转移产率。