Simple and Low-Cost Technique for Carbon Nanotube Synthesis

Currently, the methods that use microwaves to promote the growth of carbon nanotubes (CNT) employ waveguides in their configuration. We describe a method for synthesizing CNT based on the use of a microwave plasma at atmospheric pressure, and maintained by a resonant cavity. The replacement of waveguides by the resonant cavity results in deposition areas greater than 15 cm
²
, and is therefore not limited by the equipment configuration, since plasma is formed in almost the entire length of the quartz tube. As a result, confirmed by Raman spectroscopy and scanning and transmission electron microscopy, good quality carbon nanotubes were obtained, with an ID/IG ratio less than one unit in addition to the possibility of tuning the nanostructure diameter through process conditions.