ACCVD Growth, Raman and Photoluminescence Spectroscopy of Isotopically Modified Single-Walled Carbon Nanotubes

Using alcohol catalytic CVD (ACCVD) technique optimized for the efficient production of SWNTs from very small amount of ethanol, SWNTs consisting of carbon-13 isotope (SWCNTs) were synthesized. Raman scatterings from SWCNTs show no change from SWCNTs in spectrum shape except for the Raman shift frequency down-shifted as much as square-root of mass ratio 12/13. On the other hand, SWNTs with mixed 12/13 isotopes from CH3-CH2-OH and CH3-CH2-OH show different amount of down-shift in Raman spectra, suggesting that smaller amount of site-1 carbon atom (next to OH) is incorporated into SWNTs. Based on this result, the initial decomposition reaction of ethanol on metal catalyst is discussed. Furthermore, near infrared luminescence of D2O-surfactant dispersions of both SWCNTs and SWCNT were mapped. By comparing these maps, phonon sidebands of excitonic excitation were clearly identified.