Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Nanostructures at surfaces: Wires, tubes
O 52.2: Vortrag
Mittwoch, 16. März 2011, 15:15–15:30, WIL B122
Photochemical tuning of the conductivity of DNA-platinum cluster chains — •Christiane Schuster1, Thomas Härtling2, Lukas Eng3, and Michael Mertig1 — 1Technische Universität Dresden, Professur für Physikalische Chemie, Mess- und Sensortechnik, 01062 Dresden — 2Fraunhofer Institute for Non-Destructive Testing, 01109 Dresden — 3Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden
We present a self-assembly based method for the fabrication of conductive DNA-based nanowires. By means of chemical functionalization, DNA molecules were engineered into the gaps of 3 – 5 µm wide Au finger electrode arrays. Photo-induced metal deposition was then applied to grow about 5 nm Pt clusters along the molecules. At this stage, the resulting discontinuous cluster chains showed no electrical conductivity. Hence, we “welded” the Pt clusters by further photo-induced deposition of gold into the interparticle gaps and finally obtained continuous, electrically conducting nanowires. The photochemical reduction of gold takes place from a HAuCl4 solution and is catalyzed by the platinum clusters. Exploiting this catalytic activity, we obtain high spatial selectivity of the photo-induced deposition process far below the diffraction limit. Experiments were carried out on an inverted microscope, using a laser for inducing the reduction reaction, and a white-light illumination for monitoring the deposition process. The wires were analyzed by atomic force microscopy and conductivity measurements which proofed the high spatial selectivity of the method as well as the electrical quality of the wires.