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Nanowires from conjugated rigid rod molecules


Research objectives and content
The objective is to fabricate, for the first time, nanowires from conjugated rigid rod polymers, which are just one molecule long, and which are contacted by metallic nanoelectrodes. The electron transfer properties shall be measured as a function of various properties, including doping, the length of the molecular wire, and the contact properties. In preliminary experiments it has been shown recently for a series of poly(phenylene-ethinylenes) that needles with molecular dimensions self-assemble at the interface between an insulating solid substrate and an organic solution. Self-assembled nanostructures such as these needles shall be interfaced by planar electrodes with gaps on the order of 20 nm. The electrodes shall be fabricated using high-resolution e-beam lithography. Incorporation of self-assembled needles on a device into the metallic nano-gaps shall be accomplished by making use of three forces and combinations thereof: (1) Forces exerted by a scanning force microscopy tip, (2) an inhomogeneous electric field generated with the nanoelectrodes and pulling a dielectric into the gap, and (3) the high affinity of the end groups (e.g. thiols) with the metallic electrodes (e.g. gold). Doping shall be accomplished from the gas-phase. The self-assembled molecular structures shall be investigated using in-situ force microscopy in various modes including repulsive forces, non-contact, as well as intermittent contact. The analysis shall be assisted by Molecular Mechanics Calculations and Molecular Dynamics Simulations. Current voltage characteristics of the needles in the nanojunction shall be measured in order to investigate their behaviour as nanowires.
Training content (objective, benefit and expected impact)
The objective is to provide post-graduate training in a highly interdisciplinary area of research and technology, including state-of-the-art scanning probe microscopies of soft matter, self-assembly at interfaces, molecular mechanics calculations and molecular dynamics simulations, as well as electronic properties of molecular materials. It is expected that this will have important impact on various
interdisciplinary scientific areas, as well as on modern industries including an emerging nanotechnology.
Links with industry / industrial relevance (22)
The project builds directly on two projects, which have been carried out in consortia with two major electronic companies participating: ESPRIT LTR Project (PRONANO) with IBM, and a project on Molecular Electronics with SIEMENS, funded by the German Ministry for Research and Technology, indicating the high degree of interest in the potential of this approach.

Funding Scheme

RGI - Research grants (individual fellowships)


Humboldt-Universität zu Berlin
10115 Berlin

Participants (1)

Not available