Dresden 2011 – wissenschaftliches Programm

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ISS: Intersectional Sessions

ISS 5: Transport and Spectroscopy in Molecular Nanostructures I (CPP, MO, related to SYMN)

ISS 5.10: Vortrag

Mittwoch, 16. März 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.