Substrate doping effects on Raman spectrum of epitaxial graphene on SiC

In this paper, we reported a Raman scattering study of epitaxial graphene on different doped 6H-SiC (0001) substrates and investigated the substrate induced charge-transfer doping to the epitaxial graphene. We found that the charge carrier type and concentration of epitaxial graphene can be altered by SiC substrates with different doping level and doping type. This effect is comparable to that obtained by electrochemical doping. As Raman scattering is very sensitive to the doping level, the charge carrier concentration of epitaxial graphene can be estimated by the Raman G-peak shift. Our results are fundamental and may have implications for future epitaxial-graphene-based micro/nanoelectronic devices.