Raman Spectroscopy of Folded and Scrolled Graphene

    Authors

    R. Podila; R. Rao; R. Tsuchikawa; M. Ishigami;A. M. Rao

    Comments

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    Abbreviated Journal Title

    ACS Nano

    Keywords

    folded graphene; Raman spectroscopy; Fermi velocity; graphene scrolls; CARBON NANOSCROLLS; STACKING ORDER; GRAPHITE; Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience &; Nanotechnology; Materials Science, Multidisciplinary

    Abstract

    Here we examine the effects of folding and scrolling on the Raman spectra of mechanically exfoliated single- and bilayer graphene prepared on SiO2 substrates. We find that incommensurate folding in bilayer graphene results in a shift of the second-order G' band frequency, similar to that observed in folded single-layer graphene due to fold-induced changes in the phonon/electronic energy dispersion. Importantly, we show that the contrasting Raman shifts reported for the G' band frequency in folded graphene can be rationalized by taking into account the relative strength of fold-induced electron/phonon renormalization. More interestingly, we find that curvature in scrolled graphene lifts the degeneracy of the G band and results in a splitting of the G band and the appearance of low-frequency radial breathing-like (RBLM) modes. This study highlights a variety of Raman signatures for fold-induced and curvature-induced graphene and sets the stage for further theoretical and experimental studies of these novel structures.

    Journal Title

    Acs Nano

    Volume

    6

    Issue/Number

    7

    Publication Date

    1-1-2012

    Document Type

    Article

    Language

    English

    First Page

    5784

    Last Page

    5790

    WOS Identifier

    WOS:000306673800006

    ISSN

    1936-0851

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