Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)

HL 39.9: Poster

Tuesday, March 17, 2015, 14:00–20:00, Poster F

Suspended graphene nanoribbons fabricated by electron beam-induced nano-etching — •Alessio Miranda, Jens Sonntag, Benedikt Sommer, Daniel Braam, Günther Prinz, Martin Geller, and Axel Lorke — Faculty of Physics, Universität Duisburg-Essen, Lotharstraße 1 Duisburg, 47058 Germany

Suspended graphene without any contact to a substrate is the ultimate two-dimensional system based on the honeycomb lattice structure of carbon atoms. However, the fabrication of nanodevices in suspended graphene needs a processing technique that preserves ideally its lattice structure or should be at least minimally invasive. We use here a fabrication technique based on electron beam induced nano-etching, which can cut suspended graphene with a resolution down to 7 nm. We show its use for the fabrication of suspended nanoribbons (GNR) and nanoribbons with asymmetric width (nanoconstrictions). The structural quality of suspended graphene after the cut is investigated using both 2D Raman spectroscopy and electrical characterization. Comparison of Raman maps taken on the same area before and after cutting confirm that the lattice structure still has a high quality. The electrical measurements of graphene nanoribbons show the characteristic conductance diamond as a function of drain and backgate voltage. Asymmetric nanoribbons show current rectification as a function of the drain voltage. The dependence of the rectification ratio on the back gate voltage is also studied.

References: [1] C. Thiele, et al. Carbon 64, 84 (2013). [2] B. Sommer, et al., Scientific Reports, submitted (2014).