Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 102: Graphene: Interaction with the Substrate (HL jointly with DY, MA, O, TT)
O 102.3: Talk
Friday, April 4, 2014, 11:45–12:00, POT 081
Reststrahl band assisted photocurrents in epitaxial graphene layers — •P. Olbrich1, C. Drexler1, L.E. Golub2, S.N. Danilov1, V.A. Shalygin3, V.A. Shalygin3, R. Yakimova4, S. Lara-Avila5, S. Kubatkin5, B. Redlich6, R. Huber1, and S.D. Ganichev1 — 1University of Regensburg, Regensburg, Germany — 2Ioffe Institute, St. Petersburg, Russia — 3State Polytechnic University, St. Petersburg, Russia — 4Linköping University, Linköping, Sweden — 5Chalmers University of Technology, Göteborg, Sweden — 6FOM Institute for Plasma Physics, Nieuwegein, The Netherlands
We report on the observation of reststrahl band assisted photocurrents in epitaxial graphene on SiC. The samples were excited by the infrared radiation from the tunable free electron laser "FELIX" and a CO2 gas laser [1]. We show that the photoresponse due to linearly (circularly) polarized mid-infrared light is strongly enhanced (suppressed) in the vicinity of the reststrahl band of SiC. Our data, in particular a complex spectral behavior, are well described by the developed theory taking into account photon drag and photogalvanic effects affected by an enhanced light-matter interaction in the range of substrate’s negative dielectric function in its reststrahl band. Moreover, our work demonstrates that substrate phonons strongly influence the transport properties of the carriers in graphene.
[1] P. Olbrich et al., arXiv:1308.0123