CARBON SINGLE WALL NANOTUBES ELABORATION AND PROPERTIES

Co-evaporation of carbon, in the presence of helium with some other el ement as catalyst, yields interesting new molecules of the fullerene F amily which have tubular morphologies with a cross-section at the nano scale bur lengths at the macroscale. In particular, using Ni or Co bas ed mixtures as catalyst with the electric are technique, one obtains s ingle wall carbon nanotubes in large quantities, with an average diame ter of 1.4 nm and which assemble themselves in highly crystalline bund les containing a few tens of elements. These nanotubes have been obser ved, characterized and studied using high resolution microscopy techni ques. X-ray and electron diffraction have been used to characterize th e crystalline nature of individual bundles. The diameter dispersion ha s been studied in detail using Raman spectroscopy which shows impressi vely well-resolved structures of the observed modes. A majority of (10 , 10) armchair tubes is observed, but some other configurations are al so present with slightly different diameters. (C) 1998 Published by El sevier Science Ltd. All rights reserved.