Article,
Electronic structure and dynamics of optically excited single-wall carbon nanotubes
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 78 (8): 1137-1145 (May 2004)
DOI: {10.1007/s00339-003-2465-1}
Abstract
We have studied the electronic structure and charge-carrier dynamics of
individual single-wall carbon nanotubes (SWNTs) and nanotube ropes using
optical and electron-spectroscopic techniques. The electronic structure
of semiconducting SWNTs in the band-gap region is analyzed using
near-infrared absorption spectroscopy. A semi-empirical expression for
E-11(S) transition energies, based on tight-binding calculations is
found to give striking agreement with experimental data. Time-resolved
PL from dispersed SWNT-micelles shows a decay with a time constant of
about 15 ps. Using time-resolved photoemission we also find that the
electron-phonon (e-ph) coupling in metallic tubes is characterized by a
very small e-ph mass-enhancement of 0.0004. Ultrafast electron-electron
scattering of photo-excited carriers in nanotube ropes is finally found
to lead to internal thermalization of the electronic system within about
200 fs.
