Growth of vertically aligned single-walled carbon nanotubes on alumina and sapphire substrates

The synthesis of vertically aligned carbon nanotubes with submillimeter-order heights was performed using ethanol chemical vapor deposition with Co catalysts supported on Al2O3 substrates. The effects of Al2O3 in the form of amorphous alumina and single-crystalline sapphire were investigated through a characterization of the Co catalyst particles on the substrates. An important effect of Al2O3 was found to be the production of highly dense and nanosized Co particles, owing to a low surface diffusivity.