We have developed a growth system for carbon nanotubes (CNTs) based on an alcohol thermal chemical vapor deposition (A-CVD). This system, which is similar to a cold wall-type CVD system, has an additional tubular electric furnace. The additional furnace is installed at a gas inlet in order to heat the carbon source gas. In this study, we have investigated the effect of the gas inlet heating to the grown CNTs by Raman spectroscopy and scanning electron microscopy (SEM). It was found that the smaller diameter single-walled CNTs (SWCNTs) could be grown with a gas inlet heating at 800°C compared to the grown SWCNTs obtained without gas inlet heating. The two-furnace A-CVD system can provide a new method of a diameter-controlled growth of SWCNTs.
