Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 15: C/diamond I

HL 15.9: Talk

Tuesday, March 24, 2009, 11:45–12:00, POT 51

Graphene on various substrates — •Ulrich Stöberl, Ursula Wurstbauer, Werner Wegscheider, Dieter Weiss, and Jonathan Eroms — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany

So far nearly all transport experiments on graphene have been carried out using silicon dioxide (SiO₂) as a substrate. Therefore it is interesting to study electrical transport in graphene on substrates other than SiO₂. To clarify the influence of the substrate on visibility, morphology and transport properties of graphene and few layer graphene (FLG), we study graphene on molecular beam epitaxy (MBE) grown (001)-GaAs-, manganese p-doped (001) GaAs- and InGaAs-substrates. We combine scanning electron microscopy (SEM) and atomic force microscopy (AFM) to detect, pattern, and study the morphology of the graphitic layers on different substrate materials. The MBE grown substrates can be tailored in terms of morphology, polarity as well as doping and are all equipped with back-gate electrodes. From morphology and flexibility measurements we learned that graphene is quite flexible and follows continuous textures. Thin layers of carbon have the capacity to follow the morphology of the substrate from the nm- to the µm range. Low-temperature magnetotransport measurements of graphene on these substrates reveal normal electric field dependence via back gate voltages as known from reports of transport on suspended graphene or layers on SiO₂. In further studies, the influence of the substrate on position and sharpness of the Dirac-Point, intrinsic carrier density and mobility will be investigated.