Carbon nanotubes produced by arc discharge

Growth and characterization of carbon nanotubes (multiwalled and single-wall) produced by an electric are discharge are reviewed. For the preparation of multiwall nanotubes (MWNTs), an electrode of pure carbon is usually evaporated in helium gas of 200-600 Torr and sometimes in hydrogen of 50-200 Torr. For single-wall nanotubes (SWNTs), on the other hand, metals which act as catalysts for growing SWNTs are evaporated together with carbon. The catalytic activities of a variety of metals and mixtures are presented. Growth models of MWNTs and SWNTs are also discussed.