Regensburg 2004 – scientific programme
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TT: Tiefe Temperaturen
TT 17: Postersitzung II: Transport, Quantenkoh
ärenz, Quantenflüssigkeiten
TT 17.14: Poster
Tuesday, March 9, 2004, 14:30–19:00, Poster A
Conductance properties of single-molecule junctions under pulsed laser illumination — •J. U. Würfel1, S. Dantscher2, C. Kennerknecht2, W. Pfeiffer2, S. Schramm2, and H. B. Weber1 — 1Forschungszentrum Karlsruhe, Institut für Nanotechnologie, PO-Box 3640, D-76021 Karlsruhe — 2Physikalisches Institut EP1, Universität Würzburg, Am Hubland, D-97074 Würzburg
We investigate electron transport properties of single-molecule junctions, formed by the mechanically-controlled break-junction technique. Recent experiments demonstrated that we are able to contact single molecules [1]. Here, we report on measurements carried out under illumination with a femtosecond TiSa laser system. We observe a photo-induced enlargement of the conductance. As possible mechanism a thermally induced diminishment of the contact distance is discussed and contrasted to a picture of photo-excited electrons in the leads. When diode-like molecules are used, different photo-induced conductance changes for positive and negative bias voltage are observed.
[1] Phys. Rev. Lett., 88, 176804 (2002)