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HL: Fachverband Halbleiterphysik
HL 4: Carbon: Diamond, Nanotubes, and Graphene
HL 4.11: Vortrag
Montag, 14. März 2011, 13:00–13:15, POT 251
Disorder induced energy gaps in graphene nanoribbons — •Jan Dauber1, Bernat Terrés1,2, Christian Volk1,2, Stefan Trellenkamp2, Uwe Wichmann1, and Christoph Stampfer1,2 — 1JARA-FIT and II. Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany — 2Institute of Bio and Nanosystems, Forschungszentrum Jülich, 52425 Jülich, Germany
Graphene with its unique electronic properties is one of the most promising materials for future nanoelectronic applications. However, the missing band gap in graphene makes it difficult to transfer state-of-the-art electronic device concepts to a graphene-based technology. By tailoring graphene into narrow ribbons a transport and effective energy gap can be opened, which is crucial for semiconductor related applications. We show that these effective energy gaps scale inversely with the nanoribbon width and are roughly constant as function of length. The origin of these effective energy gaps and the local resonances are assumed to be related with the disorder potential arising from the substrate and the edge roughness. We present transport measurements on lithographically defined and etched graphene nanoribbons with focus on studying the influence of the disorder potential on the transport gaps. Treatments with hydrofluoric (HF) acid are used to change the disorder potential and result in different transport characteristics. With a short HF dip the disorder potential is significantly reduced and a complete HF release, which removes the underlying silicon oxide, leads to fully suspended graphene nanostructures with only edge roughness induced disorder and no substrate interaction.