Raman spectroscopy of carbon nanostructures: Nonlinear effects and anharmonicity

Abstract

We have analyzed the influence of the annealing temperature, structural disorder, and the frequency of a continuous excitation laser radiation νL on the first- and the second-order Raman spectra of several nanostructured carbon materials including single-wall carbon nanotubes (SWNT), SWNT-polymer composites, and nanostructured single-crystalline graphites. Consideration of the high-order nonlinear effects in Raman spectra and anharmonicity of characteristic Raman bands (such as G, G′, and D modes) provides important information on the vibration modes and collective (phonon-like) excitations in such 1D or 2D confined systems