Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 38: Poster III: Resistive switching (jointly with DF, KR, HL); Thermoelectric materials (Focused session); Micro- and nanopatterning (jointly with O); Ion irradiation effects

DS 38.48: Poster

Donnerstag, 29. März 2012, 17:30–19:00, Poster E

Tuning the conductivity of vanadium dioxide films by swift heavy ion irradiation — •Paul Ehrhardt¹, Hans Hofsäss¹, Hans-Gregor Gehrke¹, Johann Krauser², Christina Trautmann³, and Shriram Ramanathan⁴ — ¹II. Physikalisches Institut, Fakultät für Physik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — ²Hochschule Harz, University of Applied Sciences, Friedrichstraße 57-59, 38855 Wernigerode, Germany — ³Gesellschaft für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany — ⁴Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA

We demonstrate the generation of a persistent conductivity increase in vanadium dioxide thin films by irradiation with swift heavy ions at room temperature. VO2 undergoes a temperature driven metal-insulator-transition (MIT) at 67 °C. After the ion irradiation the conductivity of the films we observe a strong increase in conductivity below the transition temperature proportional to the ion fluence. This change in conductivity is persistent and remains after several cycles of heating. Low temperature measurements down to 15 K show no further MIT below room temperature. Although the conductivity increase after irradiation at such low fluences is due to single ion track effects, atomic force microscopy (AFM) measurements do not show surface hillocks, which are characteristic for ion tracks in other materials. AFM measurements with conducting tip give no evidence for conducting ion tracks but indicate the existence of conducting regions around poorly conducting ion tracks, possible due to stress generation.