Carbon single wall nanotubes elaboration and properties

Co-evaporation of carbon, in the presence of helium with some other element as catalyst, yields interesting new molecules of the fullerene family which have tubular morphologies with a cross-section at the nanoscale but lengths at the macroscale. In particular, using Ni or Co based mixtures as catalyst with the electric are technique, one obtains single wall carbon nanotubes in large quantities, with an average diameter of 1.4 nm and which assemble themselves in highly crystalline bundles containing a few tens of elements. These nanotubes have been observed, characterized and studied using high resolution microscopy techniques. X-ray and electron diffraction have been used to characterize the crystalline nature of individual bundles. The diameter dispersion has been studied in detail using Raman spectroscopy which shows impressively well-resolved structures of the observed modes. A majority of (10, 10) armchair tubes is observed, but some other configurations are also present with slightly different diameters. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.