We measured the near-infrared photoluminescence decay time in several different-chirality single-walled carbon nanotubes by time-resolved picosecond luminescence spectroscopy. Together with the results of resonant pump-and-probe spectroscopy this leads to a carrier lifetime in the first excited state of semiconducting nanotubes exceeding $30\mathrm{ps}$, which is one order of magnitude larger than the carrier dynamics observed in nanotube bundles. Our findings show that the absence of photoluminescence in nanotube bundles is due to a tunneling of the free carriers from semiconducting into metallic nanotubes.

• Received 20 April 2004

DOI:https://doi.org/10.1103/PhysRevB.71.033402