Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 6: Graphene: Magnetic fields (HL, jointly with O, TT)

HL 6.3: Talk

Monday, March 11, 2013, 10:00–10:15, H17

Weak Localization and Raman Study of Graphene Antidot Lattices Obtained by Crystallographically Anisotropic Etching — •Florian Oberhuber, Stefan Blien, Stefanie Heydrich, Tobias Korn, Christian Schüller, Dieter Weiss, and Jonathan Eroms — Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg

We report the crystallographically anisotropic etching of exfoliated graphene on SiO₂ substrates by applying an etching mechanism that was demonstrated to eliminate carbon atoms located on armchair sites thus leading to zigzag edges [1]. Before exposing samples to this carbothermal reaction, they were patterned with circular antidots (diameter ≈40nm) by EBL and RIE. In the subsequent carbothermal etching step the predefined holes evolved into hexagonal antidots (≈100nm).

We investigated a set of samples patterned with square lattices of hexagonal antidots and compare them to graphene patterned with lattices of circular holes investigated previously [2]. First, we compare samples by analyzing the weak localization peak in electron transport from which we obtain the phase coherence length and lengths for inter- and intravalley scattering. Second, samples were characterized by Raman spectroscopy focusing on G, D and D* peaks. In addition to the above mentioned comparison we demonstrate the influence of the etching reaction on graphene’s properties by showing a series of Raman maps acquired between consecutive sample preparation steps.

[1] Nemes-Incze et al., Nano Res. (2010)

[2] Eroms et al., New J. Phys. (2009), Heydrich et al., APL (2010)