Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 30: Inorganic/Organic Interfaces: Towards Application
O 30.2: Talk
Tuesday, March 17, 2015, 14:15–14:30, MA 043
Charge Transport through Carbon Nanomembrane Molecular Junctions — •Paul Penner1, Xianghui Zhang1, Emanuel Marschewski1, Florian Behler2, Polina Angelova1, André Beyer1, Jens Christoffers2, and Armin Gölzhäuser1 — 1Fakultät für Physik, Universität Bielefeld, Bielefeld, Germany — 2Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
Self-assembled monolayers (SAMs) of phenylthiol (PT), biphenylthiol (BPT), p-terphenylthiol (TPT) and p-quaterphenylthiol (QPT) formed on polycrystalline Au(111) are irradiated with low energy electrons and convert to carbon nanomembranes (CNMs). Molecular junctions incorporating pristine and cross-linked self-assembled monolayers (SAMs) from thiolphenyl homologues are fabricated and investigated. A two-terminal setup composed of a Ga2O3/EGaIn top electrode and the Au substrate on which SAMs are prepared as a bottom electrode was used to characterize the molecular junctions. A comparison of charge transport characteristics reveals a decrease of conductance of CNM-based junctions by one order of magnitude, as well as a conversion of asymmetric junctions with SAMs into symmetric junctions with CNMs, which could be attributed to the decoupling of CNMs from the Au substrate and the partial loss of aromaticity of CNMs after irradiation. Transition voltage (TV) spectroscopy was also employed to investigate both types of junctions. We observe the length-dependent behavior of TV in both systems and a reduction of TV of CNM-based junctions in comparison to SAM-based junctions.