Raman Spectroscopy of Graphene (abstract)

Abstract

We used micro‐Raman spectroscopy and atomic force microscopy to study variations of the Raman spectrum as a function of the number of graphene layers. Samples were prepared by micromechanical cleaving of natural graphite on a ∼300‐nm SiO2 layer. The variations of Raman G band (∼1,580 cm−1), G* band (∼2,450 cm−1), and 2D band (∼2,700 cm−1) were observed as a function of the number of graphene layers. Raman 2D band is especially sensitive to the number of graphene layers. These features are related to the electronic band structure of graphene. Moreover, the areas of different number of graphene layers were clearly identified using spatially resolved micro‐Raman imaging spectroscopy. Polarized micro‐Raman spectroscopy on single‐layer graphene shows strong polarization dependences of double‐resonance Raman intensities. The Raman intensity of the double‐resonant 2D band is maximum when the excitation and detection polarizations are parallel and minimum when they are orthogonal, whereas that of the G band is is...