WIAS Preprint No. 1693, (2012)

Self-heating effects in organic semiconductor devices enhanced by positive temperature feedback



Authors

  • Fischer, Axel
  • Pahner, Paul
  • Lüssem, Björn
  • Leo, Karl
  • Scholz, Reinhard
  • Koprucki, Thomas
    ORCID: 0000-0001-6235-9412
  • Fuhrmann, Jürgen
    ORCID: 0000-0003-4432-2434
  • Gärtner, Klaus
  • Glitzky, Annegret

2010 Mathematics Subject Classification

  • 80A20 35K05 35C05 65N08

Keywords

  • heat conductivity, organic semiconductor, C60, crossbar electrodes, Joule heating, device temperature, thermal resistance, break down, analytical solution, heat flow equation, 3D simulation, finite volume method

Abstract

We studied the influence of heating effects in an organic device containing a layer sequence of n-doped / intrinsic / n-doped C60 between crossbar metal electrodes. A strong positive feedback between current and temperature occurs at high current densities beyond 100 A/cm2, as predicted by the extended Gaussian disorder model (EGDM) applicable to organic semiconductors. These devices give a perfect setting for studying the heat transport at high power densities because C60 can withstand temperatures above 200° C. Infrared images of the device and detailed numerical simulations of the heat transport demonstrate that the electrical circuit produces a superposition of a homogeneous power dissipation in the active volume and strong heat sources localized at the contact edges. Hence, close to the contact edges, the current density is significantly enhanced with respect to the central region of the device, demonstrating that three-dimensional effects have a strong impact on a device with seemingly one-dimensional transport.

Appeared in

  • Organic Electronics, 13 (2012) pp. 2461--2468 under the title ``Self-heating effects in organic semiconductor crossbar structures with small active area''

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