Observations of theD-band feature in the Raman spectra of carbon nanotubes

We examine the behavior of the D-band feature in the Raman spectra of single-walled carbon nanotube (SWNT) bundles, observed between 1250 and 1450 cm^-1, as a function of the laser excitation energy. We used three SWNT samples with different diameters, and show that the D-band behavior of SWNTs differs from sp^2 carbons, depending on whether the SWNTs are metallic or semiconducting, and shows a frequency ₃ that is dependent on nanotube diameter.