Berlin 2008 – scientific programme

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DS: Fachverband Dünne Schichten

DS 29: Nanoengineered Thin Films

DS 29.6: Talk

Thursday, February 28, 2008, 19:15–19:30, H 2013

Electrical characterization of conducting ion tracks in insulating tetrahedral amorphous carbon — •Hans-Gregor Gehrke¹, Anne-Katrin Nix¹, Johann Krauser², Christina Trautmann³, and Hans Hofsäss¹ — ¹II. Physikalisches Institut Göttingen, Germany — ²Hochschule Harz, Wernigerode, Germany — ³Gesellschaft für Schwerionenforschung, Darmstadt, Germany

We investigated the formation and the electrical characteristics of quasi one-dimensional conducting tracks in tetrahedral amorphous carbon (ta-C) produced by swift heavy ion irradiation. The ta-C films with thicknesses of about 100 nm were created with mass-separated ion beam deposition (MSIBD) on highly conducting silicon substrates with a deposition energy of 100 eV yielding into a sp³ bond fraction of approximately 80%. The films were irradiated afterwards with 1 GeV ²³⁸U ions with fluences between 10⁸ and 10¹¹ ions/cm². The high electronic energy loss of about 30 keV/nm of the swift heavy ions graphitizes the film locally along the ion trajectory. Thus, conducting nanowires embedded in an insulating matrix were achieved. The presence of the tracks could be confirmed with atomic force microscopy (AFM) using a conducting cantilever and applying a bias voltage. The conductance of the tracks is several orders of magnitude higher than that of the surrounding matrix. Temperature depended electrical characterization (300 K - 15 K) were performed on track ensembles with special focus on improving the contact pads.