Attempt to synthesize carbon nanotubes by hot-wire chemical vapor deposition

Synthesis of carbon nanotubes was attempted by hot-wire chemical vapor depo sition using a mixture of C2H2 and NH3 gases. Substrates used were crystall ine (c-) Si and amorphous (a-) SiO2 coated with Ni films of 30 nm in thickn ess as a catalyst for nanotube formation. Scanning electron microscopy (SEM ) images showed that micron-sized grains were present in the deposit on the c-Si substrate, whereas nano-sized grains were evident in the deposit on t he a-SiO2 substrate. Nanotube formation could not be confirmed by SEM, but there is evidence of the possible formation of nanotubes on the Ni-coated a -SiO2 substrate. (C) 2001 Elsevier Science BN All rights reserved.