Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 43: Graphene I

O 43.9: Talk

Wednesday, March 24, 2010, 12:30–12:45, H31

Electrical transport measurements in graphene and graphenoids from pyrolized self-assembled monolayers — •Andrey Turchanin¹, Dirk Weber², Matthias Büenfeld¹, Joachim Mayer³, Christian Kisielowski⁴, Thomas Weimann³, and Armin Gölzhäuser¹ — ¹Physik supramolekularer Systeme, Fakultät für Physik, Universität Bielefeld — ²Physikalisch-Technische Bundesanstalt, Braunschweig — ³Gemeinschaftslabor für Elektronenmikroskopie, RWTH Aachen — ⁴National Center for Electron Microscopy, Berkeley

We investigate the transition of insulating ultrathin (∼1 nm) carbon nanosheets (graphenoid sheets) to conducting graphene. Self-assembled monolayers (SAM) of aromatic biphenyl molecules are cross-linked by electrons. The cross-linking results in mechanically stable graphenoid sheets with the thickness of a single molecule and arbitrary sizes. The nanosheets can then be lifted from their surface and transferred to another solid substrate or holey structure, where the nanosheets become suspended free-standing nanomebranes [1]. Upon annealing (pyrolysis) at higher temperatures (up to ∼1300K) the nanosheets transform into a graphitic phase that consists of nanosize graphene patches. This transformation is accompanied by a drop of the sheet resistivity from ∼10⁸ to 10 kΩ/sq [2]. We characterize the insulator to conductor transition by complementary spectroscopic and microscopic techniques and electrical transport measurements.

[1] C. T. Nottbohm et al, Ultramicroscopy 108, 88 (2008)

[2] A. Turchanin et al, Adv. Mater. 21, 1233 (2009)