Effect of nitrogen doping on Raman spectra of multi-walled carbon nanotubes

Multi-walled carbon nanotubes (CNTs) and nitrogen-doped carbon (CNx) nanotubes have been synthesized by the aerosol-assisted chemical vapour deposition (CVD) method. The samples were prepared from toluene and acetonitrile taken in different proportion. The structure of CNTs and CNx nanotubes was compared using first- and second-order Raman spectra. The disorder-induced D band was found to up-shift with increase of the acetonitrile fraction. The I-D/I-G and I-G/I-G ratios showed the opposite dependence on the doping level of CNTs. Both kinds of the substitute nitrogen: graphitic-like and pyridinic-like contribute to the disorder in CNx nanotube layers. [GRAPHICS] The first- and second-order Raman spectra of CNTs produced from toluene and CNx nanotubes produced from acetonitrile. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim