Experimental assignment of phonon symmetry of G+ and G- peaks from single-walled carbon nanotubes

Abstract

Raman scattering spectroscopy is widely used for the characterization of single-walled carbon nanotubes (SWCNTs). Although the G-band is one of the most important peaks of SWCNTs, the phonon symmetry of the most and second strong peaks in the G-band (G+ and G- peaks) is still veiled. Here, we show the experimental evidence of their phonon symmetry by using single-suspended SWCNT samples and polarized Raman scattering spectroscopy. The G+ and G- peaks come from A symmetry phonons, and the resonance effect to the excitonic excitation and the depolarization effect are dominant in the polarization characteristics of G+ and G- peaks.