Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 41: Inorganic/Organic Interfaces

O 41.3: Poster

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

Comparison of Electronic Transport Measurements on Carbon Nanomembranes using Conductive Probe Atomic Force Microscopy and Ga₂O₃/EGaIn Top Electrodes — •Emanuel Marschewski, Xianghui Zhang, Paul Penner, and Armin Gölzhäuser — Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld, Germany

Aromatic self-assembled monolayers (SAMs) can be cross-linked via irradiation with low energy electrons and convert to carbon nanomembranes (CNMs). We compare the electronic transport measurements on pristine and cross-linked self-assembled monolayer of 4’-nitro-1,1’-biphenyl-4-thiol (NBPT) on polycrystalline Au(111)/mica and Au/Si by using two techniques. The conductance along with friction force mapping of pattern arrays of non-cross-linked and cross-linked NBPT-SAMs is conducted by using conductive probe atomic force microscopy (CP-AFM), where the cross-linked regions clearly show lower conductance and lower friction force. The application of soft Ga₂O₃/EGaIn top electrodes allows for a quantitative analysis of conductance and transition voltages (TVs) of molecular junctions incorporating NBPT-SAMs and NBPT-CNMs, respectively. The conductance reduces more than one order of magnitude, despite the fact that the layer thickness reduces slightly upon electron irradiation. The reduction of the TV by ∼0.5 V is also found in the NBPT-CNM based junctions. In addition, a suppression of conductivity in CP-AFM measurements implies that there could exist a certain amount of highly conducting pinholes, which may explain the discrepancy between the two techniques.