Observation of Raman G-band splitting in top-doped few-layer graphene

Abstract

An experimental study of Raman scattering in N-layer graphene as a function of the top layer doping is reported. At high doping level, achieved by a CHF_3 plasma treatment, we observe a splitting of the $G$ band in the spectra of bilayer and 4-layer graphene (N even), whereas the splitting is not visible in case of monolayer and trilayer graphene (N odd). The different behaviors are related to distinct electron-phonon interactions, which are affected by symmetry breaking and Fermi level position in different ways in the various N-layer graphenes. In trilayer graphene, a weakening of the electron-phonon coupling as a function of the Fermi energy induces a hardening of all zone-center in-plane optical phonon modes, like in monolayer graphene. On the other hand, in 4-layer graphene two distinct trends are observed in the G band as a function of doping, suggesting the presence of two different groups of electron-phonon interactions, like in bilayer graphene.

7 pages, 6 figures, to be published in PRB

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Cited by in corpus (6)

• The electronic properties of bilayer graphene
• Imaging Stacking Order in Few-Layer Graphene
• Raman signature of electron-electron correlation in chemically doped few-layer graphene
• Direction-Controlled Chemical Doping for Reversible G-Phonon Mixing in ABC Trilayer Graphene
• Nanomechanical strain concentration on a 2D nanobridge within a large suspended bilayer graphene for molecular mass detection
• Reversible optical doping of graphene