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 I-D/I-G ratio less than one unit in addition to the possibility of tuning the nanostructure diameter through process conditions.