Growth behavior of carbon nanotubes on Fe-deposited (001) Si substrates

Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are used to investigate the growth behavior of carbon nanotubes on the Fe-deposited Si (001) substrates by thermal chemical vapor deposition (CVD). The Fe films are deposited for 20 s-20 min by pulse-laser deposition. SEM results show that the growth characteristics of carbon nanotubes strongly depend on the Fe film deposition time. TEM results show that the CVD growth at 800 degreesC causes the continuous Fe films to be broken up into nanoparticles 10-50 nm across and discontinuous islands 100 nm-1.1 mum in size. It is shown that the Fe nanoparticles are essentially required for the formation of aligned carbon nanotubes. We show direct evidence that a base growth mode is responsible for the growth of carbon nanotubes in the present work. (C) 2001 American Institute of Physics.