To illustrate the importance of the substrate material on which the TMDC is deposited, we focus on the surface roughness and the dielectric constant. The substrate roughness is particularly relevant for TMDC monolayers as an uneven surface enhances carrier scattering. Moreover, since most carrier transport occurs in the few TMDC layers located closest to the electrodes, such carrier scattering also affects bulk TMDC crystals. We have measured bulk WSe2 on (smooth) glass and