Formation of Graphite Layers during Carbon Nanotubes Growth

Abstract

We have investigated carbon products deposited on large catalyst islands during carbon nanotube growth by thermal chemical vapor deposition on a Fe–Ni catalyst film, using cross-sectional analysis by transmission electron microscopy and scanning electron microscopy. It was found that carbon atoms covering on the surface of Fe–Ni large islands form graphite layers with high crystallinity at a temperature as low as 700°C. The growth mechanism of the graphite layers can be explained in terms of precipitation of diffused carbon atoms from the inside of large catalyst islands.