Temperature and substrate dependence of structure and growth mechanism of carbon nanofiber

The carbon nanofibers were grown on Ni/Si and Ni/Ti/Si substrates in 1 atm CH4 atmosphere at 640 degrees C and 700 degrees C by thermal chemical vapor deposition method. The carbon nanofibers were characterized by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectrometry for morphology, microstructure, and crystallinity. The electron emission property of carbon nanofibers was also investigated by current-voltage (I-V) measurement. The results showed that the solid amorphous carbon nanofibers could be grown on Ni/Si substrate at 640 degrees C through tip growth mechanism, the carbon nanotubes could be grown on Ni/Si substrate at 700 degrees C through tip growth mechanism, and the carbon nanotubes could be grown on Ni/Ti/Si substrate at 700 degrees C through root growth mechanism. (C) 2008 Elsevier B.V. All rights reserved.