Ultrafast carrier dynamics in single-walled carbon nanotubes probed by femtosecond spectroscopy.
Ultrafast carrier dynamics in individual semiconducting single-walled carbon nanotubes was studied by femtosecond transient absorption and fluorescence measurements. After photoexcitation of the second van Hove singularity of a specific tube structure, the relaxation of electrons and holes to the fundamental band edge occurs to within 100 fs. The fluorescence decay from this band is dependent on the excitation density and can be rationalized by exciton annihilation theory. In contrast to fluorescence, the transient absorption has a distinctly different time and intensity dependence for different tube structures, suggesting a branching to emissive and trap states following photoexcitation.
Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Ying-Zhong
YZ
Ma
Jens
J
Stenger
Jorg
J
Zimmermann
Sergei M
SM
Bachilo
Richard E
RE
Smalley
R Bruce
RB
Weisman
Graham R
GR
Fleming