Ultrafast optical-pump terahertz-probe spectroscopy of the carrier relaxation and recombination dynamics in epitaxial graphene.
The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump terahertz-probe spectroscopy. The conductivity in graphene at terahertz frequencies depends on the carrier concentration as well as the carrier distribution in energy. Time-resolved studies of the conductivity can therefore be used to probe the dynamics associated with carrier intraband relaxation and interband recombination. We report the electron-hole recombination times in epitaxial graphene for the first time. Our results show that carrier cooling occurs on subpicosecond time scales and that interband recombination times are carrier density dependent.
School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, USA. pag25@cornell.edu
Paul A
PA
George
Jared
J
Strait
Jahan
J
Dawlaty
Shriram
S
Shivaraman
Mvs
M
Chandrashekhar
Farhan
F
Rana
Michael G
MG
Spencer