Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 60: Graphene: Electronic Properties (O jointly with DS, HL, MA, TT)
O 60.10: Talk
Wednesday, April 2, 2014, 18:15–18:30, WIL C107
Electronic and Transport Properties of Epitaxial Graphene on the Atomic Scale — •Philip Willke1, Thomas Druga1, Alexander Schneider2, Rainer Ulbrich1, and Martin Wenderoth1 — 1IV. Physikalisches Institut, Georg-August Universität Göttingen, Germany — 2Lehrstuhl für Festkörperphysik, FAU Erlangen, D-91058, Germany
The application of graphene in future devices requires a thorough understanding of its transport properties on the nanometer scale. We present a scanning tunneling potentiometry study at 6 K of electron scattering in mono- and bilayer graphene on n-doped SiC. Using STP we combine the imaging of local transport fields and sample topography. By probing simultaneously the thermovoltage signal [1] created due to slightly different temperatures of sample and tip, we can moreover obtain sensitive information on the electronic structure at the Fermi energy. We demonstrate how both transport and electronic information can be disentangled from STP measurements. We identify substrate steps and monolayer-bilayer junctions as local scattering centers which impede the electronic current and create local voltage drops that we compare to recent measurements at 72 K. [2] Moreover, wrinkles and substrate inhomogeinities have been identified as further sources of scattering. We acknowledge the financial support by the SPP 1459 "Graphene".
[1] K. J. Engel, M. Wenderoth, N. Quaas, T. Reusch, K. Sauthoff and R.Ulbrich, Phys. Rev. B 63, 165402 (2001)
[2] S. H. Ji et al., Nature Materials 11, 114-119 (2012)