Surface-enhanced and normal Stokes and anti-Stokes Raman spectroscopy of single-walled carbon nanotubes

Surface enhancement factors of at lease 10(12) for the Raman scattering of single-walled carbon nanotubes in contact with fractal silver colloidal clu sters result in measuring very narrow Raman bands corresponding to the homo geneous linewidth of the tangential C-C stretching mode in semiconducting n anotubes. Normal and surface-enhanced Stokes and anti-Stokes Raman spectra are discussed in the framework of selective resonant Raman contributions of semiconducting or metallic nanotubes to the Stokes or anti-Stokes spectra, respectively, of the population of vibrational levels due to the extremely strong surface-enhanced Raman process, and of phonon-phonon interactions.