We present a study of free carrier photo-generation and multi-carrier bound states, such as biexcitons and trions (ionized excitons), in semiconducting single-walled carbon nanotubes. Pump-and-probe measurements performed with fs pulses reveal the effects of strong Coulomb interactions between carriers on their dynamics. Biexciton formation by optical transition from exciton population results in an induced absorption line (binding energy 130 meV). Exciton-exciton annihilation process is shown to evolve at high densities towards an Auger process that can expel carriers from nanotubes. The remaining carriers give rise to an induced absorption due to trion formation (binding energy 190 meV). These features show the dynamics of exciton and free carriers populations.
@article{arxiv.1302.1590,
title = {Biexciton, single carrier, and trion generation dynamics in single-walled carbon nanotubes},
author = {Bertrand Yuma and Stéphane Berciaud and Jean Besbas and Jonah Shaver and Silvia M. Santos and Saunab Gosh and R. Bruce Weisman and Laurent Cognet and Mathieu Gallart and Marc Ziegler and Bernd Hönerlage and Brahim Lounis and Pierre Gilliot},
journal= {arXiv preprint arXiv:1302.1590},
year = {2013}
}