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HL: Fachverband Halbleiterphysik
HL 22: Graphene 2 (Joint Session with TT)
HL 22.12: Vortrag
Dienstag, 23. März 2010, 12:30–12:45, H21
Time-resolved spectroscopy of graphene — •Tim Botzem1, Tobias Plötzing1, Bart Szafranek2, Daniel Schall2, Daniel Neumaier2, and Heinrich Kurz1 — 1Institut für Halbleitertechnik, RWTH Aachen, Gemany — 2AMICA, AMO GmbH, Aachen, Gemany
In graphene the coupling of various quasi particles accounts for the ultrafast temporal evolution of nonequilibrium carrier distributions. Hence understanding of the relaxation processes is crucial for designing high speed electronic and photonic devices. For investigating the involved quasi particle interactions we apply femtosecond pump-probe spectroscopy (17 fs temporal resolution) on exfoliated graphene mono- and bilayer flakes prepared on transparent sapphire substrates. Relaxation of hot carriers takes place within the first few tens of femtoseconds after excitation, revealing the strong coupling between the different quasi particles involved. A detailed analysis of the dependence on excitation fluence, carrier concentration and fabrication method will be given.