Solar production of single-wall carbon nanotubes: growth mechanisms studied by electron microscopy and Raman spectroscopy

We report here some studies of the growth mechanisms of single-wall carbon nanotubes (SWNTs) produced by the solar method as a function of the experim ental conditions and the nature of catalysts. A large set of transmission e lectron microscopy (TEM) pictures seems to confirm the existence of one dom inant growth mechanism, close to the model proposed by Saito et al., whatev er the used catalyst might be. Nevertheless, the Raman spectra clearly show that the change of catalyst induces differences in diameter, structure, an d electronic properties of SWNTs.