Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 11: Transport
HL 11.8: Vortrag
Montag, 22. März 2010, 15:45–16:00, H14
Negative bend resistance in a nanoscale epitaxial graphene cross junction — •Sonja Weingart1, Claudia Bock1, Ulrich Kunze1, Florian Speck2, Thomas Seyller2, and Lothar Ley2 — 1Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — 2Technische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg
We report on the observation of inertial-ballistic transport in nanoscale cross junctions fabricated from epitaxial graphene grown on SiC(0001). Ballistic transport is indicated by a negative bend resistance which vanishes with increasing temperature.
The advanced morphology of graphene films on SiC(0001) grown in an Ar atmosphere [1] yields improved transport properties [2] and an electron mean free path of le = 58 nm at T= 4.2 K. The mean free path exceeds the device dimensions for a 50 nm wide orthogonal cross junction, and a negative bend resistance of R12,43≈ −170 Ω observed at T= 4.2 K indicates ballistic transport.
With increasing temperature a transition from the ballistic to the diffusive transport regime is indicated by a change of sign in R12,43.
For cross junctions with leads of width b = 80 nm no negative bend resistance is observed, which is in accordance with the estimated mean free path (le < 80 nm).
[1] K.V. Emtsev, et al., Nature Mater. 8, 203 (2009).
[2] S. Weingart, et al., Physica E, doi:10.1016/j.physe.2009.11.006.