Growth of Horizontally-Aligned Single-Walled Carbon Nanotubes on Sapphire Surface by Needle-Scratching Method

Abstract

We report the growth of single-walled carbon nanotubes (SWNTs) over metal nanoparticles which are formed by scratching sapphire surface with metal wires. The chemical vapor deposition over sapphire substrate scratched with Fe and Co metal wires gives horizontally aligned SWNTs, while no nanotube growth is observed for Au, Mo, and Ni wires. This result suggests that the nanoparticles scattered from Fe and Co wires act as the catalyst for SWNT growth, being different from the previously proposed substrate-catalyzed reaction mechanism. Further, we study the effects of the flow rates of CH 4 –H 2 gases during the SWNT growth on the nanotube density and diameter.