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O: Fachverband Oberflächenphysik
O 60: Graphene: Electronic Properties (O jointly with DS, HL, MA, TT)
O 60.4: Vortrag
Mittwoch, 2. April 2014, 16:45–17:00, WIL C107
Electrical Transport in Freestanding Epitaxial Graphene: Evidence of an AB-Stacked Bilayer — •Johannes Jobst1,2, Shriram Shivaraman3, Michael G. Spencer3, and Heiko B. Weber2 — 1Leiden University, Kamerlingh Onnes Laboratorium, P.O. Box 9504, NL-2300 RA Leiden, Netherlands — 2Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — 3School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
We investigate the properties of freestanding epitaxial graphene devices, which are created using a photo-electrochemical etching technique. This technique allows to selectively remove the silicon carbide (SiC) substrate on which the graphene was grown by thermal decomposition of SiC. We focus on completely freestanding devices of various geometries and devoid of any graphene-substrate interactions. We prepare freestanding Hall bars in order to study the low-temperature transport and Shubnikov-de Haas oscillations. We find evidence that the buffer layer is transformed to an additional graphene layer upon the etching process, and that the formed bilayer is AB stacked. Inhomogeneities in the buffer layer or introduced during the etching process are discussed.