Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 50: Graphene and Carbon Nanotubes

HL 50.8: Vortrag

Donnerstag, 25. März 2010, 11:30–11:45, H15

Magnetotransport behaviour of Graphene on GaAs — •Ulrich Wurstbauer, Ursula Wurstbauer, Jonathan Eroms, Werner Wegscheider, and Dieter Weiss — Institut für Experimentelle und Angewandte Physik, Universität Regensburg

The influence of the substrate on the transport properties of graphene generated recently some interest. To clarify the role of the underlying substrate, we perform (magneto)-transport experiments of graphene and few-layer graphene on (001)-GaAs substrates, grown by molecular beam epitaxy. The graphitic flakes on GaAs were detected and their morphology was characterized by scanning electron and atomic force microscopy.

We found that graphene follows the curvature of the sustaining substrate very closely. Low-temperature transport measurements of graphene on these substrates reveal a conventional electric field dependence indicated by a resistance maximum at the charge neutrality point. It turns out that the intrinsic doping on GaAs substrates is always hole like. Magnetotransport measurements in the low-field region display a superposition of universal conductance fluctuations and weak localization, both more pronounced on GaAs substrates than on SiO₂ and visible up to 75 K. Additionally, in the high field region Hall-effect and Shubnikov-de Haas oscillations were observed indicating quantized transport.