Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 99: Organic Semiconductors: Transport
HL 99.5: Vortrag
Freitag, 30. März 2012, 10:30–10:45, EW 203
Positive feedback between Joule heating and current density in organic devices based on C60 — •Axel Fischer1, Paul Pahner1, Björn Lüssem1, Karl Leo1, Reinhard Scholz1, Thomas Koprucki2, Jürgen Fuhrmann2, Annegret Glitzky2, and Klaus Gärtner2 — 1Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden — 2Weierstraß-Institut für Angewandte Analysis und Stochastik, Mohrenstraße 39, 10117 Berlin
We have studied the influence of heating effects on the device performance in an organic device containing a layer sequence of n-doped / intrinsic / n-doped C60 between crossbar metal electrodes. Due to the fact that C60 can withstand temperatures above 200∘C, these devices give a perfect setting for studying the heat transport. At high current densities beyond 100 A cm−2, a strong positive feedback between current and temperature is observed, as predicted by the extended Gaussian disorder model (EGDM) applicable to organic semiconductors [1]. Approximate analytical studies and detailed 3D numerical simulations for the stationary heat transport problem reveal the temperature distribution. The result is confirmed by thermal imaging of the device. Additionaly, strong heating at the edges of the device is obtained and cannot be understood quantitatively by assuming homogeneous Joule heating in the active volume. Instead, 3D effects have to be included even for the seemingly 1D electrical transport pathways between the two electrodes. [1] R. Coehoorn, W. F. Pasveer, P. A. Bobbert, and M. A. J. Michels, Phys. Rev. B 72, 155206 (2005).