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TT: Fachverband Tiefe Temperaturen

TT 78: Graphene: Electronic Properties (organized by O)

TT 78.7: Vortrag

Mittwoch, 2. April 2014, 17:30–17:45, WIL C107

Optical characterization of atomically precise graphene nanoribbons — •Richard Denk¹, Michael Hohage¹, Jinming Cai², Pascal Ruffieux², Roman Fasel², and Peter Zeppenfeld¹ — ¹Experimental Physics, JKU Linz, Altenbergerstrasse 69, 4040 Linz, Austria — ²nanotech@surfaces, EMPA, Überlandstasse 129, 6800 Dübendorf, Switzerland

Graphene nanoribbons (GNRs) promise high potential for future nanoscale electronic devices. While 2-dimensional graphene is semimetallic, electron confinement and edge effects in narrow (<10nm) GNRs can result in the opening of a band gap. The electronic and optical properties, however, strongly depend on the structural details of the GNRs. Only recent advances in the bottom-up fabrication of atomically precise GNRs [1] have enabled reliable experimental investigations of well-defined GNRs.

We have studied the fabrication process and the optical properties of GNRs on Au(788) using reflectance difference spectroscopy (RDS), taking advantage of the optical anisotropy due to the uniaxial alignment of the GNRs parallel to the step edges of the vicinal Au(788) surface. We find that the optical properties of the GNRs are highly anisotropic and dominated by three excitonic transitions, in excellent agreement with theoretical calculations.

[1] J. Cai at el, Nature, 466 (2010) 470.