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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.40: Poster

Wednesday, March 16, 2011, 17:30–21:00, P4

Micro Four-Point-Probe Conductivity Measurements on Graphene — •Edward Perkins, Bjarke Jørgensen, Liv Hornekaer, and Philip Hofmann — Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, Aarhus 8000C, Denmark

Four-point-probe measurements are a well-known technique for measuring conductivity independent of contact resistances. In these experiments, we apply this method at the micrometer scale to investigate surface transport. By varying the separation and geometry of the contacts it is possible to distinguish between two-dimensional and three-dimensional conductivity. This technique thus allows us to study the details of transport at surfaces in a wide range of materials.

Measurements from epitaxial graphene on silicon carbide at room temperature and 77 K are presented. The characteristic two-dimensional transport is analysed and compared to transport in other materials. Simulations of the potential are also considered with a view to understanding the details of the conductivity profile.