Diameter Control of Arc Produced Multiwall Carbon Nanotubes by Ambient Gas Cooling

Abstract

The cooling effect of an ambient gas on arc discharge for the growth of carbon nanotubes has been investigated in terms of the diameter of the nanotube. A small diameter nanotube with high purity is successfully obtained by cooling of ambient He gas using a water-cooling coil placed around the arc discharge. Furthermore, the width of the diameter distribution becomes narrow under this condition. The effective cooling of the ambient gas induces high plasma temperature, which is evaluated by optical emission spectroscopy.