Low temperature, field-dependent mobility in pentacene thin-film transistors.

ORAL

Abstract

We measure the field-effect and saturation mobility of Au bottom contact thin-film polycrystalline pentacene field-effect transistors while varying temperature, channel length, and gate voltage. We utilize Au bottom contacts without a wetting layer, and achieve contact resistance as low as 1 k$\Omega $-cm despite disturbance of the pentacene morphology at the drain and source electrodes. By measuring multiple channel lengths, we extract a contact-resistance free mobility. We confirm this value using an alternative technique in which we short the source and drain electrodes and make two terminal measurements of the capacitance and loss between these electrodes and the gate as a function of frequency. We discuss the result of field-dependent mobility in the context of Poole-Frenkel theory to rationalize the non-linear dependence of drain current on drain voltage, and test the predictions of recently developed models for transport in such systems.

*Supported by the Laboratory for Physical Science at UM.

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Authors

  • Adrian Southard

    • Center for Nanophysics and Advanced Materials (CNAM) and the Department of Physics (DOP), University of Maryland (UM)

  • Vinod Sangwan

    • Laboratory of Physical Sciences (LPS), CNAM,, and DOP, UM
    • University of Maryland

  • Dan Lenski

    • CNAM and the DOP, UM

  • Michael Fuhrer

    • CNAM and the DOP, UM

  • Ellen Williams

    • University of Maryland, College Park
    • Department of Physics and University of Maryland Materials Research Science and Engineering Center, University of Maryland, College Park, MD 20742
    • University of Maryland
    • LPS, CNAM, and the DOP, UM
    • Physics Department, University of Maryland, College Park, MD 20742
    • Materials Research Science and Engineering Center, Center for Nanophysics and Advanced Materials, Dept of Physics, Univ. of Maryland, College Park, MD
    • University of Maryland College Park
    • Dept. of Physics, U. of Maryland - College Park
    • Department of Physics and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD 20742-4111, USA