Growth of vertically aligned carbon nanotubes on a silicon substrate by a spray pyrolysis method

Vertically aligned carbon nanotubes on a silicon substrate were synthesized by a spray pyrolysis method using the methyl ester of Helianthus annuus oil as a carbon source, ferrocene as a catalyst precursor and argon as a carrier gas. Results show that Fe catalyst nanoparticles are formed from ferrocene in-situ on the silicon substrate. As-grown vertically aligned carbon nanotubes are well graphitized as shown by Raman spectra, transmission electron microscopy images and X-ray diffraction patterns. The diameter of the carbon nanotubes is around 10-30 nm and their wall thickness is around 10 nm. The content of catalyst in the products is negligible.