Electronic structure characterization of an individual single-walled carbon nanotube by in situ electrochemical surface-enhanced Raman scattering spectroscopy.

We present an electronic structural analysis of an individual single-walled carbon nanotube (SWNT) by employing electrochemical surface-enhanced Raman scattering (SERS). An isolated SWNT was supported on a well-defined Au nanodimer structure, which possesses a localized surface plasmon resonance (LSPR) field at the nanogap, and highly intense SERS spectra were obtained for the SWNT at the gap region. The absolute potential of the Fermi level of the isolated SWNT in an ionic liquid was determined from the electrochemical potential dependence of the SERS intensity showing the dependence on the chirality of SWNTs. The electronic structural change in an isolated SWNT by ozone oxidation treatment was also analyzed. The results indicate that the electrochemical SERS technique is a powerful tool for detailed analysis of the electronic structure of isolated SWNTs.