A comparative Raman study of graphite, single-walled, and multi-walled carbon nanotubes

The present article presents a comparative Raman study of graphite, single-walledcarbon nanotube (SWCNT),and multi-walled carbon nanotube (MWCNT) materials. The Raman spectra of graphite, SWCNTs, and MWCNTs have been recorded using two different excitation wavelengths, 532 and 785 nm in the region, 1800-1200 cm-1. The G-bands of SWCNTs and MWCNTs observed at both the excitation wavelengths were fitted taking three peaks into account with Breit-Wigner-Fano (BWF) and Lorentzian line shape functions. The contribution of both BWF and Lorentzian line shapes to the Raman asymmetric G-band shows a mixture of semi conducting and metallic CNTs in the SWCNT and MWCNT bundles. The apparent Young's modulus of SWCNT and MWCNT materials was determined using the intensity ratio, ID/IG obtained from the Raman spectroscopic analysis, and we found that the SWCNTs have a larger value of the apparent Young's modulus compared with that of MWCNTs. © 2009 John Wiley & Sons, Ltd.