Metal Particle Catalyst Formation from Thin Films for the Creation of Vertically Aligned Carbon Nanotube Structures.

摘要

This work contains research associated with the metal catalysts used in the formation of vertically aligned carbon nanotube (VACNT) films through catalytic chemical vapour deposition (CCVD). The solid-state dewetting process of thin metal films is studied using Ni. In the dewetting process, grain growth is followed by hole nucleation and growth at grain boundaries due to thermal grooving and curvature induced surface diffusion respectively. Coarsening continues after the percolation limit due to Ostwald and Smoluchowski ripening. A 2 nm Cr50Fe35Ni15 catalyst is found to grow the tallest VACNT films. This catalyst is found to have excellent stability against coarsening. This stability is found to be the result of Cr oxide that forms before the sample enters the CCVD reactor, but does not reduce in the reactor environment. The VACNT film is comprised of multi-walled carbon nanotubes (MWCNT) produced through base growth and whose average diameter is ∼12 nm.