Buffer layers inhomogeneity and coupling with epitaxial graphene unravelled by Raman scattering and graphene peeling

摘要: The so-called buffer layer (BL) is a carbon rich reconstructed formed during SiC (0001) sublimation. The covalent bonds between some atoms in this and underlying silicon makes it different from epitaxial graphene. We report systematical statistical investigation of the BL signature its coupling with graphene by Raman spectroscopy. Three different BLs are studied: bare obtained direct growth (BL0), interfacial and SiC (c-BL1) without above (u-BL1). To obtain latter, we develop mechanical exfoliation removing an epoxy-based resin or nickel layer. BLs are ordered-like on whole BL temperature range. BL0 signature may vary sample to sample but forms patches same terrace. u-BL1 share similar properties BL0, albeit with more variability. These have strikingly larger overall intensity than top. The signal high frequency side onset upshifts upon coverage, unexplainable simple strain effect. Two fine peaks (1235, 1360 cm1 ), present for monolayer absent transferred findings point to BL.