Fig. 4

It is 242 cm\(^{-1}\) (MoSe\(_{2}\), A\(_{\mathrm {1g}}\), black dash line), 251 cm\(^{-1}\) (WSe\(_{2}\), A\(_{\mathrm {1g}}\), blue dash line) and 257 cm\(^{-1}\) (WSe\(_{2}\), 2LA (M), orange dash line) in the Raman spectra. The 249 cm\(^{-1}\) (WSe\(_{2}\), A\(_{\mathrm {1g}}\), red dash line) and 254 cm\(^{-1}\) (WSe\(_{2}\), 2LA (M), green dash line) are the red shift of the oscillation mode WSe\(_{2}\) A\(_{\mathrm {1g}}\) and WSe\(_{2}\), 2LA (M), respectively. The Raman red shift peak is only observed in the MWS-800, MWS-900 and MWS-1000