Radiative lifetime of excitons in carbon nanotubes

2019-10-01 17:23:45

energy lifetime dependent excitons radiative

责任者: Perebeinos, Vasili;Tersoff, J.;Avouris, Phaedon 单位: IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598, United States 来源出处: Nano Letters,2005,5(12):2495-2499 摘要: 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. © 2005 American Chemical Society. 关键词: Nanotubes;Excitons;Carbon;Semiconductor materials;Electrons;Phonons;Electron-hole correlations;Bethe-Salpeter equation;Intrinsic phonons;Diameter-dependent energy splittings