Carbon nanotubes: synthesis and applications

A highly needed major breakthrough in the nanotubes technology for electronic applications is the development of a fabrication method capable of producing well organized nanotube structures, with uniform nanotubes and reproducible electronic properties. In our Institute we are developing site-selective CVD nanotubes synthesis both on flat substrates with patterned catalyst layers and in nanotemplates. Several types of flat substrates such as silicon, silicon oxide, silicon nitride and porous silicon have been prepared. Transition metal catalysts, such as nickel and iron, have been investigated as seeds to nucleate the growth of nanotubes. Various CVD process parameters ( carbon gas precursor type and percentage in the gas mixture, use of etching or carrier gases in the gas mixture and deposition temperature) have been investigated to obtain ordered arrays of reproducible nanotubes. In this paper we report the results of this investigation showing the formation of CNTs on different substrates and different catalysts. The CNTs structural characterization by SEM and TEM observations is reported.