Radiative lifetime of excitons in carbon nanotubes.
We calculate the radiative lifetime and energy bandstructure of excitons in semiconducting carbon nanotubes within a tight-binding approach including the electron-hole correlations via the Bethe-Salpeter equation. In the limit of rapid interband thermalization, the radiative decay rate is maximized at intermediate temperatures and decreases at low temperature because the lowest-energy excitons are optically forbidden. The intrinsic phonons cannot scatter excitons between optically active and forbidden bands, so sample-dependent extrinsic effects that break the symmetries can play a central role. We calculate the diameter-dependent energy splittings between singlet and triplet excitons of different symmetries and the resulting dependence of radiative lifetime on temperature and tube diameter.
Perebeinos
Vasili
V
IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598, USA. vperebe@us.ibm.com
Tersoff
J
J
Avouris
Phaedon
P
D003198:Computer Simulation; D004553:Electric Conductivity; D004583:Electrons; D006207:Half-Life; D008956:Models, Chemical; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010316:Particle Size; D011874:Radiometry; D013696:Temperature
D037742:Nanotubes, Carbon