Thermal-CVD System Designed for Growth of Carbon Nanotubes

We report a study on a thermal chemical vapor deposition (CVD) system optimized for the growth of well packed and vertically aligned carbon nanotubes (CNTs) on uncoated silicon substrates. The process of synthesis involves the co-evaporation of a carbon precursor and a metal catalyst in a nitrogen atmosphere inside a high temperature furnace. Beside the formation of CNTs, depending in particular on the deposition temperature, other carbon structures can be deposited, such as nanographite. We show the growth results analyzed by different characterization techniques (electron microscopy, porosity and thermal stability investigations, micro-Raman spectroscopy). In addition, we report an investigation on the development of secondary transversal vortex flows caused by the effects of distribution of temperatures inside the growth system, in order to correlate them with the growth results.