Intersubband decay of 1-D exciton resonances in carbon nanotubes
NANO LETTERS, 8 (1):
87-91 (января 2008)DOI: {10.1021/nl0720915}
Аннотация
We have studied intersubband decay of E-22 excitons in semiconducting
carbon nanotubes experimentally and theoretically. Photoluminescence
excitation line widths of semiconducting nanotubes with chiral indicess
(n,m) can be mapped onto a connectivity grid with curves of constant (n
- m) and (2n + m). Moreover, the global behavior of E-22 line widths is
best characterized by a strong increase with energy irrespective of
their (n-m)mod(3) = +/- 1 family affiliation. Solution of the
Bethe-Salpeter equations shows that the E-22 line widths are dominated
by phonon assisted coupling to higher momentum states of the E-11 and
E-12 exciton bands. The calculations also suggest that the branching
ratio for decay into exciton bands vs free carrier bands, respectively
is about 10:1.