Influence of Gas-Phase Reactions on the Growth of Carbon Nanotubes

Abstract

The effect of gas-phase reactions on the growth of carbon nanotubes is investigated by a new synthesis method of infrared light local heating chemical vapor deposition where only the substrate can be heated. The simulation of temperature distributions surrounding the heated substrate shows that the region with high temperatures over 600 °C is enlarged with the increase of the substrate temperature. The expansion of the high-temperature region is speculated to result in the growth of carbon nanotubes at a substrate temperature of 770 °C and the successful growth of carbon nanotubes with a higher density at a higher temperature of 900 °C. It is analyzed that polymerization reactions of acetylene gas that occurred in the high-temperature region generate unsaturated carbon chains mainly comprising C4H4. These unsaturated carbon chains, in addition to the acetylene gas, with a high temperature should be important carbon sources for the growth of carbon nanotubes.