Synthesis of carbon nanotubes on metallic substrates by a sequential combination of PECVD and thermal CVD

Carbon nanotubes were synthesized from acetylene and hydrogen gas mixture directly on stainless steel plates by sequential combination of rf PECVD and thermal CVD. PECVD was used for nucleation and initial growth of carbon nanotubes while thermal CVD was utilized for further growth of them. In this way decoupling of nucleation and growth of carbon nanotubes was realized, and growth of carbon nanotubes was enhanced compared to growth by PECVD. Synthesized carbon nanotubes were curly in shape, and proper pretreatment of the substrate surface was required for the satisfactory growth of carbon nanotubes. Carbon nanotubes could be fabricated into electrodes for electric double layer capacitors without any further treatment. With an electrolyte composed of lithium hexafluorophosphate, ethylene carbonate and diethyl carbonate, charge/discharge test showed specific capacitance in the range of 33-82 F/g.