Schlüsselwörter
(Englisch)
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DNA; molecular electronics; nanoelectronics; nanophysics; biophysics
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Alternative Projektnummern
(Englisch)
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EU project number: IST-1999-13099
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Forschungsprogramme
(Englisch)
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EU-programme: 5. Frame Research Programme - 1.2.8 Generic R&D activities
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Kurzbeschreibung
(Englisch)
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See abstract
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Partner und Internationale Organisationen
(Englisch)
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Coordinator: Technische Universiteit Delft (NL)
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Abstract
(Englisch)
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The handling and positionning of molecules over lithographically patterned electrodes is of crucial importance for the realization of molecular devices. It turns out that molecular combing can damage the molecules during the stretching process due to the relatively large forces involved (>100pN). We developped a stretching and positioning technique based on a dielectrophoretic effect. By applying an intense ac-field (about 106 V/m at 1 MHz) to specially designed electrodes we can achieve a softer and more precise positioning of the DNA molecules on Si wafer surfaces. A further advantage of the technique resides in the binding of the molecules directly to the metallic electrodes at which the field is applied as has been observed on aluminum and gold electrodes essentially.
Transport measurements performed on devices comprising a few DNA molecules assembled with the above technique as well as usual molecular combing show essentially no conductance except in very rare cases. We have performed experiments in different conditions and environements. In particular, we varied the humidity and performed experiments in vacuum and in the presence of oxygen to test for potential doping effects. We also prepared underetched structures in oder to test free-standing molecules. A series of DNA molecules prepared in different conditions are currently under test to check for potential effects linked to the type of counterions.
Experiments performed on DNA fibers with diameters in the micrometer range yielded conductivities in the range 10-6 to 10-5 S/m. Interestingly, we could observe variations in the conductivity of the fibers upon changing the type of salts in the preparation buffer. The fibers prepared in presence of divalent cations showed an increased conductivity.
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Datenbankreferenzen
(Englisch)
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Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. +41 31 322 74 82
Swiss Project-Number: 99.0618
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