In this paper the environmental effects on the vibrational properties of individual carbon nanotubes were studied by means of Raman spectroscopy. The individual nanotubes were first synthesized by catalytic chemical vapour depositon method. Then their geometric structure was determined by electron diffraction and high-resolution electron microscopy. The intrinsic experimental relationship between RBM frequency and the tube diameter was obtained and certain deviations from the expected 228/d relationship were found. The effect of the substrate was identified as the most probable explanation for these experimental observations. In order to quantify the origins of deviations, we propose a comparison between our experimental data and calculations performed in the framework of elasticity theory.

Keywords: individual carbon nanotubes, Raman spectroscopy, radial breathing modes, environmental effects

In this paper a method for the atomic structure analysis of single-walled and multi-walled carbon nanotubes based on the combination of Raman spectroscopy and electron diffraction is presented. We discuss the main criteria of this method and give an example of index-assignment of individual double-walled carbon nanotube. We argue that the combination of several techniques gives the most accurate and unambigous structure identification.

Keywords: individual carbon nanotubes, Raman spectroscopy, electron diffraction, electron microscopy