Abstract: In this paper, under the catalytic effect of nickel particles electro-deposited on Ni substrate, self-aligned carbon nanotubes were synthesized by microwave plasma chemical vapor deposition with a mixture of methane and hydrogen gases at 510 ℃. During the process of nanotubes growth, the total pressure in the chamber was kept at 3 kPa, the microwave plasma input power was 500 W, and the flow rates of H₂ and CH₄ were 50 and 1 mL/min, respectively. The aligned features and hollow structure have been verified by scanning electron and transmission electron microscopic images. As the nanotubes grow, the nickel cap remains on the tip of the carbon nanotubes. The nanotubes′diameter is about 70 nm and they have bamboo structures. Because of the strong etching ability of hydrogen plasma and the low volume ratio of H₂/CH₄, no carbonaceous particles attached to the carbon nanotubes were found. It demonstrats that MWPCVD is a very efficient process for the synthesis of the aligned carbon nanotubes at a low temperature. The aligned CNTs grown on Ni substrate at such a low temperature are suitable for device fabrication.

Key words: Aligned carbon nanotubes, Microwave plasma chemical vapor deposition, Low temperature, Ni substrate