  Raman and photoluminescence (PL) measurements were performed on suspended and
supported MoS2 up to 6 trilayers (TLs). The difference in the dielectric
environment of suspended and supported MoS2 does not lead to large differences
in the PL or Raman spectra. Most of the apparent difference in the PL intensity
can be explained by the interference effect except for 1TL MoS2. The positions
of the Raman peaks are not much different between suspended and supported MoS2.
The relative intensities, on the other hand, show some differences between
suspended and supported samples. In particular, the inter-layer vibration modes
are enhanced near resonance with C excitons, with the breathing modes becoming
relatively stronger. Up to 4 breathing modes are resolved in suspended 6TL
MoS2.
