Supramolecular Surface Chemistry

Understanding the electronic transport through layered systems comprising organic functional layers in direct contact to semiconductor surfaces is of major importance for future applications in nanoelectronics, photovoltaics and sensors. In this project we are interested in creating new molecular architectures based on organized growth of surface-attached organic semiconductors on nanoscale devices through directed regular stacking of bifunctional oligoarenes. We focus on the deposition of self-assembled monolayers of alkyl and aryl phosphonates (SAMPs) onto silicon/silicon oxide substrates. These SAMs can serve as a basis for the preparation of novel three-dimensional, organized bilayers of anthracene diphophonates, using techniques of coordination chemistry under controlled conditions by deposition of organometallic linkers onto the monolayers. Duplex stacks of dense monolayers can be prepared by a simple sequence of SAMP formation followed first by distal surface activation through coordination chemistry and then by introduction of the second monolayer unit.



 

Current densities as a function of substrate bias for two different organophosphonate SAMs on highly p-doped Si.

Structural analysis by QCM, AFM, and XRR indicated homogeneous growth of the duplexes and not random multilayer formation. In particular, we can show that resistive and capacitive behaviors of these stacks can be analyzed using impedance spectroscopy, and data can be analyzed using basic equivalent resistance-capacitor circuit models to parse the contributions of the individual components to the capacitance of the overall ensemble. In the group of M. Tornow the electrical transport through the monolayered SAMPs is further investigated by measuring the current-voltage (I-V) characteristics using a two terminal configuration set-up (hanging Hg drop) or by studying the transport characteristics in Si nano-gap devices.

Selected Publications:

Bora A.; Pathak A.; Liao K.-C.; Vexler M. I.; Kuligk A.; Cattani-Scholz A.; Meinerzhagen B.; Abstreiter G.; Schwartz J.; Tornow M. “Organophosphonates as model system for studying electronic transport through monolayers on SiO2/Si surfaces”, Appl. Phys. Lett. 2013, 102, 241602.

Cattani-Scholz A.; Liao K.-C.; Bora A.; Pathak A.; Hundschelld C.; Nickel B.; Schwartz J.; Abstreiter G.; Tornow M. “Molecular Architecture: Construction of Self-Assembled Organophosphonate Duplexes and Their Electrochemical Characterization”, Langmuir 2012, 28, 7889−7896

Cattani-Scholz A.; Liao K.-C.; Bora A.; Pathak A.; Krautloher M.; Nickel B.; Schwartz J.; Tornow M.; Abstreiter G. “A New Molecular Architecture for Molecular Electronics”, Special Insert from DFG in Angew. Chem. Ed. Int. Ed. Engl. 2011, 37, A11-A16.

Collaborations:

Marc Tornow, Molekularelektronik, Technische Universität München

Jeffrey Schwartz, Department of Chemistry, Princeton University, USA

Open positions:

if you would like to join us as an internship or master student on this project, please contact Anna Cattani-Scholz. 

 

 

TUM Technische Universität München TUM Technische Universität München Physik Department Elektrotechnik und Informationstechnik TUM Technische Universität München
 

Events & News

17 Jan 2018

ERC Consolidator Grant for Gregor Koblmüller   more

16 Jan 2018

Light-steering of spin-polarized currents in topological insulators   more

10 Aug 2017

Best Poster Awards for Ganpath Veerabathran and Alexander Andrejew at iNOW 2017   more

27 Jun 2017

Best Poster Award at Nanowire Week for Jochen Bissinger   more

15 Mar 2017

Dr. Kai Müller admitted to the “Junges Kolleg” of the Bavarian Academy of Sciences   more

Seminars

March 12, 2018

Two-dimensional coherent spectroscopy of a semiconductor microcavity   more

March 05, 2018

Diamond-organic photovoltaics   more