Contacting Molecules - Chemistry in Molecular Electronics

By Ilona Kretzschmar

Yale University, New Haven, CT

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The study of the basic electron transport mechanism through molecular systems has been made accessible by fabrication techniques that create metallic contacts to a small number of organic molecules. In my talk, I will discuss some of the groundbreaking discoveries such as the measurement of the conductance through a single molecule using a break junction, the demonstration of molecular diodes/transistors, and molecular-scale systems that show reversible switching behavior. Despite these exciting discoveries new theoretical and experimental studies show that molecular devices are extremely sensitive towards the nature and quality of the contacts. Questions such as: (i) what does the contact look like, (ii) is the contact changed by the electronic measurement, (iii) is the contact stable over time and as a function of temperature need to be answered. It has become necessary to spend time and research efforts on the characterization of metal-molecule contacts. In spite of great efforts, we still understand very little about the electron-transfer process through molecular junctions. Often, we cannot even draw the energy band diagram for the molecular junctions prepared and therefore are not able to distinguish between different electron transport mechanisms. In my talk, I will present new I(V,T) and IETS results obtained from a Au-S-C8H16-S-Au junction, which give insight into these questions. I will also discuss a new planar device structure developed at Yale and the utilization of electrochemistry as a quality monitor in molecular electronics.


Ilona Kretzschmar received her Diploma (1996) and PhD (1999) degrees in Chemistry from the Technical University of Berlin. During her graduate studies with Professor H. Schwarz, she studied reactions of metal cations with organic molecules in the gas phase employing Fourier-transform ion-cyclotron resonance (FTICR) and Guided-Ion Beam (GIB) mass spectrometry. From 2000 to 2002, she was a Feodor-Lynen postdoctoral fellow at Harvard University, working on hydrocarbon radical-rearrangement reactions on clean and modified metal surfaces. She joined the Department of Electrical Engineering at Yale University in 2002 where she is currently a postdoctoral research associate working with Professor M. A. Reed. Her present areas of research focus on: nano/micro fabrication, self-assembly, and molecular electronics.

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  • Ilona Kretzschmar (2004), "Contacting Molecules - Chemistry in Molecular Electronics,"

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