Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Graphene: Electronic Properties, Structure and Substrate Interaction
O 44.12: Poster
Dienstag, 8. März 2016, 18:15–20:30, Poster E
High quality graphene on boron nitride prepared by polymer free dry transfer and contacting techniques for combined STM and electrical transport measurements — •Tjorven Johnsen, Daniel Montag, Felix Jekat, Martin Grob, Nils Freitag, Peter Nemes-Incze, and Markus Morgenstern — II. Physikalisches Institut B, RWTH Aachen, Otto-Blumenthal-Straße, 52074 Aachen
The charge carrier mobility of graphene is mainly determined by the substrate and adsorbates on the graphene flake. High quality graphene samples are prepared by either suspending the graphene flake or by encapsulating it in hexagonal boron nitride [1,2]. These devices, however, are not accessible for surface sensitive probes like scanning tunnelling microscopy (STM). Here we present a novel transfer technique employing a mica substrate to pick up a boron nitride flake and a graphene flake one after another from SiO2. The graphene flake is contacted using shadow mask evaporation. Thereby, we eliminate any polymers from the preparation process which are a major source of adsorbates. This is required for combined STM and electrical transport measurements. With these samples we aim to measure symmetry broken states of the quantum hall effect in graphene both with STM and transport measurements.
[1]Du et al., Nat. Nanotechnol. 3, 491 - 495 (2008)
[2]Banszerus et al., Sci. Adv. 1, e1500222 (2015)