Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Transport and Spectroscopy in Molecular Nanostructures I (related to SYMN, jointly with MO)
CPP 32.10: Talk
Wednesday, March 16, 2011, 16:30–16:45, ZEU 160
Electronic transport through organophosphonate monolayers on silicon/silicon dioxide substrates — •Achyut Bora1, Anshuma Pathak1, Kung-Ching Liao2, Anna Cattani-Scholz3, Gerhard Abstreiter3, Jeffrey Schwartz2, and Marc Tornow1 — 1Institut für Halbleitertechnik, TU Braunschweig, Germany — 2Department of Chemistry, Princeton University, NJ, USA — 3Walter Schottky Institut, TU München, Germany
Understanding the electronic transport through layered systems of organic functional layers on semiconductor surfaces is of major importance for future applications in nanoelectronics, photovoltaics and sensors. We have prepared self-assembled monolayers (SAMs) of 9,10-diphenyl-2,6-diphosphono-anthracene and 11-hydroxyundecyl phosphonic acid precursors on highly p-doped silicon surfaces coated with a ~1 nm SiO2 layer. Contact angle, AFM and ellipsometry evidenced the homogeneity of the formed SAMs, and their thickness was determined to be 0.82±0.07 nm and 1.13±0.09 nm, respectively. We provided large area electrical contacts on top of the SAMs by a hanging Hg drop electrode. The measured I-V characteristics revealed an enhanced conductance of the aromatic vs. the aliphatic compounds, with current densities of the order of 10 A/m2 and 0.01 A/m2, at 0.5 V, respectively. We analyzed the data in terms of non-resonant tunneling through the combined oxide-SAM barrier and found good qualitative agreement up to 0.2 V bias. Preliminary measurements on organized bilayers of anthracene bisphosphonates that were grown using techniques of coordination chemistry will be discussed, too.