Deep UV Raman Spectroscopy of Epitaxial Graphenes on Vicinal 6H-SiC Substrates
We report microscopic Raman scattering studies of epitaxial graphene grown on SiC substrates using a deep-ultraviolet (UV) laser excitation at 266 nm to elucidate the interaction between the graphene layer and the substrate. The samples were grown on the Si-face of vicinal 6H-SiC (0001) substrates by sublimation of Si from SiC. The G band of the epitaxial graphene layer was clearly observed without any data manipulation. Increasing the number of graphene layers, the peak frequency of the G-band decreases linearly, while the peak width and the intensity increase. The G-band frequency of the graphene layers on SiC is higher than those of exfoliated graphene, which has been ascribed to compression from the substrate.
Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller
S. Kamoi et al., "Deep UV Raman Spectroscopy of Epitaxial Graphenes on Vicinal 6H-SiC Substrates", Materials Science Forum, Vols. 645-648, pp. 611-614, 2010