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HL: Fachverband Halbleiterphysik

HL 15: C/diamond I

HL 15.13: Vortrag

Dienstag, 24. März 2009, 12:45–13:00, POT 51

Graphene-based nanoelectronics — •Soeren Neubeck, Frank Freitag, L. A. Ponomarenko, Rui Yang, A. K. Geim, and K. S. Novoselov — Department of Physics, University of Manchester, Manchester M13 9PL, UK

Graphene, a monolayer of Carbon atoms arranged in a honeycomb-lattice, holds strong promise for microelectronic applications in the post-Silicon age. Still, a current technological problem is, that graphene remains conducting even in the limit of virtually zero carrier concentration.

Recent theoretical and experimental work has shown, that it is possible to introduce an energy gap in graphene by confining its geometrical dimensions.

Here, we use an atomic force microscope (AFM) to manipulate graphene films on a nanoscopic length scale. By means of local anodic oxidation with an AFM-tip we are able to structure isolating trenches into single-layer graphene flakes, down to a trench size of less than 30nm in width. Using this technique, we demonstrate the fabrication of a single-layer graphene quantum dot. The device consists of a nanometre-sized graphene island, that is coupled to source and drain electrodes via two narrow constrictions. Low-temperature transport measurements of this device reveal Coulomb blockade, and Coulomb diamonds, characteristic of quantum dots, have been measured. A charging energy of the dot of 10meV could be extracted, which corresponds to the geometric dimensions of the dot structure formed.