Variable temperature high resolution far infrared absorption measurements were carried out for single walled carbon nanotubes samples with different diameter distributions. At a temperature where kBT is significantly lower than the phonon energy, the broad absorption features as observed in room temperature become well resolved optical transitions. Lineshape analysis shows that the most of the transitions observed in the region are consistent with phonon transitions instead direct absorption from small-bandgap semiconducting nanotubes. The energies of the transitions are consistent with the phonon modes associated with circumferential motions such as squashing modes and higher order circumferential vibrations.
Proceedings Title: Symposium C: Fundamentals of Low-Dimensional Carbon Nanomaterials
Conference Dates: November 29-December 3, 2010
Conference Location: Boston, MA
Conference Title: Materials Research Society Fall Meeting
Pub Type: Conferences
carbon nanotubes, material science, nanotechnology, THz metrology