Raman Vibrational Properties of Carbon Nanotubes with the Radiation Defect Formation

Abstract

Studies of changes in the crystal structure of multi-walled carbon nanotubes (MWNT) during the high-energy electron irradiation (E _e  = 1.8 MeV) with doses from 3.0 to 10.0 MGy are carried out by means of the analysis of the Raman vibrational spectra. It is shown that defects generated by the electron beam irradiation are accompanied by an increase in the interlayer correlations as a consequence of interlayer links and local variations in the geometry of MWNT. The generation of the structural defects leads to the drop in the integral intensities of the G- and D-bands in the Raman scattering spectrum and to the splitting of the G-band into several components. These results are supported by the manifestation of new vibrational modes with increase in the fluence of irradiation which is an indication of the reconstruction of the structure and geometry of MWNT and, respectively, of their symmetry.

Keywords:

• electron irradiation
• multi-walled carbon nanotubes
• Raman scattering

Acknowledgments

This work was partly supported by the joint Ukrainian-Lithuanian grant and the “Dnipro” Program. The authors are also thankful to Prof. V. Gulbinas and Dr. G. Niaura for valuable discussions.