Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 35: Graphene - Characterization and Devices (jointly with DS, HL, MA, and O)

TT 35.3: Talk

Wednesday, March 13, 2013, 10:00–10:15, H17

C–axis transport in graphite and few–layered–graphene — •Ole Pfoch, Yuri Koval, Michael Enzelberger, and Paul Müller — Department of Physics and Interdisciplinary Center for Molecular Materials, Universität Erlangen

Electrical transport in single or few layered graphene was intensively investigated during the last decade. However, most experiments were performed with electronic transport in the plane. Measurements in perpendicular direction are rare and the results are rather sensitive to materials properties. For instance, the literature data for the anisotropy of the electrical conductivity in plane and along the c–axis varies between 100 and 10 000. One of the reasons for the wide spread of anisotropy data might be a significant influence of structural defects. We reduce the influence of these defects by decreasing the cross section of the measured structures down to 2× 2 µm². Mesa type structures were prepared by e–beam lithography and O₂–plasma etching. The influence of the mesa size on the c–axis conductivity and its temperature dependence were investigated. We have found that the c–axis conductivity is rather sensitive to the prehistory of the sample and to the origin of the graphite material. We present our recent results and discuss the mechanism of c–axis electrical transport.