title: Carrier relaxation in epitaxial graphene photoexcited near the Dirac point.
abstract: We study the carrier dynamics in epitaxially grown graphene in the range of photon energies from 10 to 250 meV. The experiments complemented by microscopic modeling reveal that the carrier relaxation is significantly slowed down as the photon energy is tuned to values below the optical-phonon frequency; however, owing to the presence of hot carriers, optical-phonon emission is still the predominant relaxation process. For photon energies about twice the value of the Fermi energy, a transition from pump-induced transmission to pump-induced absorption occurs due to the interplay of interband and intraband processes.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany. s.winnerl@hzdr.de
authors.forename: S
authors.initials: S
authors.lastname: Winnerl
authors.forename: M
authors.initials: M
authors.lastname: Orlita
authors.forename: P
authors.initials: P
authors.lastname: Plochocka
authors.forename: P
authors.initials: P
authors.lastname: Kossacki
authors.forename: M
authors.initials: M
authors.lastname: Potemski
authors.forename: T
authors.initials: T
authors.lastname: Winzer
authors.forename: E
authors.initials: E
authors.lastname: Malic
authors.forename: A
authors.initials: A
authors.lastname: Knorr
authors.forename: M
authors.initials: M
authors.lastname: Sprinkle
authors.forename: C
authors.initials: C
authors.lastname: Berger
authors.forename: W A
authors.initials: WA
authors.lastname: de Heer
authors.forename: H
authors.initials: H
authors.lastname: Schneider
authors.forename: M
authors.initials: M
authors.lastname: Helm