Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 33: Graphene

O 33.2: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

The influence of the subtrate roughness on the electronic properties of sidewall graphene nanoribbons — •Johannes Aprojanz, Jens Baringhaus, Julia Wiegand, Michael Oestreich, and Christoph Tegenkamp — Institut für Festkörperphysik, Leibniz Universität Hannover, Germany

Graphene nanoribbons (GNR), epitaxially grown on the sidewalls of silicon carbide (SiC) mesa structures, have shown exceptional transport properties such as ballistic conduction within a single channel and electronic mean free paths of up to 15 µm [1]. We present a detailed study of the growth process of sidewall GNR using scanning probe and electron microscopy as well as Raman spectroscopy. Focussing on the influence of the substrate roughness, the density of terrace steps and the step height can be precisely controlled by a resistive "face-to-face" heating treatment The local electronic properties are investigated by means of a 4-tip STM. The roughness of the SiC and of the mesa sidewalls is identified as detrimental to the electronic performance of sidewall GNR. The mean free path of the ribbons is shown to be directly dependent on the substrate terrace width. For a high density of terrace steps, a transition from ballistic to one dimensional diffusive transport is observed. In addition, Raman spectra show a selective graphene growth on the mesa sidewalls with a I(D)/I(G) ration below 0.1, which indicates high quality graphene nanostructures.
Baringhaus et al., Nature 506, 349 (2014)