Abstract Submitted to the    NANOTUBE'04 Conference:

A highly needed major breakthrough in the carbon nanotubes technology for electronic applications is the development of a fabrication method capable of producing well organized nanotube structures, with reproducible electronic properties. In our Institute we have been developing site-selective CVD synthesis both on flat substrates with patterned catalyst layers and in nanotemplates, in order to get ordered arrays of vertically aligned nanotubes. Several types of substrates such as silicon, silicon oxide and silicon nitride have been prepared. Transition metal catalysts, such as nickel, have been considered as seeds to nucleate the growth of nanotubes. Various CVD process parameters, such as carbon gas precursor type (methane and acetylene) and percentage in the gas mixture, use of etching or carrier gases (ammonia and argon) in the gas mixture and deposition temperature, have been investigated to obtain organized and reproducible structures of carbon nanotubes. In this work we present some results on the CNTs synthesis obtained on flat substrates, with evaporated Ni layers, 2 - 4 nm thick, as catalyst, by varying the CVD process parameters. The CNTs structural characterization by SEM and TEM observations is reported. Further insights into the mechanism of carbon nanotube growth can be inferred.