Multi-Excitation-Laser Raman Analysis of Chirality-Controlled Single-Walled Carbon Nanotubes with Free Electron Laser Irradiation during Growth

Abstract

Single-walled carbon nanotubes (SWNTs) were fabricated by chemical vapor deposition using alcohol as a feeding gas of carbon. From the results of Raman spectroscopy with four kinds of exciting laser and consideration of chirality using the Kataura plot and chirality map, we found that the SWNTs grew with sizes from 0.92 to 1.41 nm in diameter, the possible chirality of which was 30. Metallic and semiconducting SWNTs grew. However, when irradiating 800 nm free-electron laser (FEL) during growth, the SWNTs of 1.1 nm diameter grew with a reduced possible chirality of 5, the electric property of which could be semiconducting. We revealed that the irradiation of FEL was effective to control the chirality of SWNTs to achieve ultrahigh-dense field effect devices.