Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 52: Transport: Graphene 2 (jointly with MA, HL, DY, DS, O)
TT 52.3: Talk
Friday, March 30, 2012, 10:00–10:15, BH 334
Transport in clean side-gated graphene nanoribbons — •Bernat Terrés1,2, Jan Dauber1,2, Uwe Wichmann1, Stefan Trellenkamp2, and Christoph Stampfer1,2 — 1JARA-FIT and II. Institute of Physics B, RWTH Aachen, 52074 Aachen, Germany — 2Peter Grünberg Institut (PGI-8/9), Forschungszentrum Jülich, 52425 Jülich, Germany
Graphene is a two dimensional form of crystalline carbon with unique electrical properties. However, due to its gap-less nature it is hardly possible to implement concepts of state-of-the-art electronic devices. Recently, it has been shown that by tailoring graphene into narrow ribbons an effective band gap can be induced. Extensive studies have been reported on the transport mechanism in graphene nanoribbons and although being successfully demonstrated as tunneling barriers in quantum dots, graphene nanoribbons show a Coulomb blockade dominated transport behavior. In this work we report on the effects of a symmetrically applied side gate voltage on clean (hydrofluoric acid treated) graphene nanoribbons. In particular we show low-temperature experiments where the overall conductance can be tuned up to a level of about 8e2/h. Measurements show evidence that the local resonances in the transport gap can be strongly suppressed by adjusting the side-gate voltages. In summary, the high conductance values together with the observation of onsets of quantized conductance plateaus at integer multiples of 2e2/h indicates that the disorder potential can be dramatically reduced, even though the transport mechanism is still mainly dominated by substrate and rough-edge induced disorder.