  Pump-dependent photoluminescence imaging and 2nd order photon correlation
studies have been performed on individual single-walled carbon nanotubes
(SWCNTs) at room temperature that enable the extraction of both the exciton
diffusion constant and the Auger recombination coefficient. A linear
correlation between these is attributed to the effect of environmental disorder
in setting the exciton mean free-path and capture-limited Auger recombination
at this lengthscale. A suppression of photon antibunching is attributed to
creation of multiple spatially non-overlapping excitons in SWCNTs whose
diffusion length is shorter than the laser spot size. We conclude that complete
antibunching at room temperature requires an enhancement of exciton-exciton
annihilation rate that may become realizable in SWCNTs allowing for strong
exciton localization.
