Organized networks of helically wound single-walled C-nanotubes

We report experimental evidence on the possibility to synthesize organized networks of helically wound single-walled carbon nanotubes (SWNTs). In particular, our experimental approach produces ordered layers constituted by twisted bundles formed by interweaved single-walled nanotubes. Scanning electron microscopy (SEM), scanning tunnelling microscopy (STM) and high resolution transmission electron microscopy (HRTEM) been used to investigate the inner structure of the nanotubes deposits. The results of our studies strongly suggest that aligned arrays of helically wrapped nanottibe bundles can be obtained by controlling the spatial dispersion of metallic clusters at the substrate surface. Whereas the spatial distribution of the catalyst govern the packing of the bundles, the dimension of metallic clusters is responsible for the nucleation of single-walled nanotubes from the same location and the consequent wrapping. (C) 2004 Elsevier B.V. All rights reserved