The feasibility of the Hot Filament assisted CVD (HFCVD) technique to favor the catalytic growth of carbon nanotubes has been investigated. Single wall nanotubes (SWNT) with a high degree of crystallinity and purity have been grown with a density which could be varied by changing either the catalyst thickness or the synthesis conditions. In particular, one aspect of the technique was to allow self assembling of suspended bundles or isolated SWNTs. (c) 2005 Published by Elsevier B.V.