Catalytic Growth of Carbon Nanostructures in Glow Discharge

Glow discharge ignited between a graphite cathode and a copper anode was applied to conduct a process of carbon nanostructure growth in an argon atmosphere. During the first stage of the experiment, the samples mounted on the cathode were heated up till turning red, which significantly increased the thermionic emission and caused the formation of cathode arc spots on the sample surface. The arcing with a period of 3 to 5 s was maintained for 5 more minutes. As a result, a number of craters were observed on the samples, which were investigated using the SEM technique. Carbon nanotubes and bundles of them were found along the whole surface of the samples, and the tips of the nano- and microsized structures were capped by the copper particles, which states in favor of the catalytic growth. The yield of the carbon structures was richer in the craters and the regions at the proximity to them. In addition, a carbon deposit was taken from the anode and studied by use of TEM. In this case, typical nanostructures resemble the branches of spruce trees or balls of rolled nanotubes with a diameter of about 15 to 30 nm; at that, the anode nanostructures do not show any traces of the copper catalyst. Thus, the proposed setup is suitable to grow various carbon nanostructures in a catalytic process in the presence of copper.