The growth of bunched and multi-circularly wrapped carbon nanotubes on bulk magnetic alloys by microwave enhanced hot-filament CVD with a dilute gas of ammonia

¹ Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
² Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
³ Materials Science Center, National Tsing Hua University, Hsinchu, Taiwan
⁴ Department of Material Science and manufacturing, Chinese Culture University, Taipei, Taiwan

Corresponding author: jtlue@phys.nthu.edu.tw

Received: 3 December 2003
Revised: 10 May 2004
Accepted: 27 August 2004
Published online: 21 December 2004

Abstract

Bunched and multi-circularly wrapped carbon nanotubes (CNT) are observed to grow on alloy substrates based on iron group metals and copper by a microwave enhanced hot-filament method with a dilute gas of ammonia at a proper RF self-bias. The grown size of CNTs embodied in the grain sizes of conducting bulk alloy catalysts such as Cu-Ni, Cu-Fe, Cu-Co, and Cu-Ni-Fe-Co are controlled by a precursor time of hydrogen plasma etching. Species with different structural features and homogenization of CNTs samples are produced crucially attributed to various reactant gases and self-bias induced by the radio frequency field.