Characterization of Fe-catalyzed carbon nanotubes grown by thermal chemical vapor deposition

Abstract

The growth of carbon nanotubes (CNTs) on Fe catalytic films by thermal chemical vapor deposition has been investigated. Fe thin films deposited on Si substrates agglomerate to nanoparticles after heat treatment. The Fe nanoparticles are easily oxidized to Fe2O3 after the synthesis, but the nanoparticles during the CNT synthesis are shown to be in the liquid iron phase due to the reducing force of NH3. This is revealed by cross-sectional transmission electron microscopy examinations of the nanoballs and the Fe inclusions along with relevant chemical analyses. The CNT growth mode and mechanism with a Fe catalyst was very similar to that with a Ni catalyst in thermal chemical vapor deposition method. (C) 2002 Elsevier Science B.V. All rights reserved.