Dual-catalyst growth of vertically aligned carbon nanotubes at low temperature in thermal chemical vapor deposition

Vertically aligned carbon nanotubes (CNTs) were successfully synthesized at 550 °C on Ni-coated Si substrate placed parallel to Pd plate as a dual catalyst and a tungsten wire filament. The CNT length increased with increasing gas flow rates even at such a low growth temperature, suggesting that the hydrocarbon gases were sufficiently decomposed in the presence of tungsten wire filament and dual Pd catalyst. The difference of growth behavior from that at high temperature was explained by introducing the Ni–C solid solution, which enables the carbon atoms to diffuse more easily even at low temperature.