Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 31: Organic semiconductors
HL 31.11: Talk
Wednesday, March 29, 2006, 17:15–17:30, POT 51
Comparison of two-dimensional device simulations with potentiometry measurements on pentacene OFETS — •R Scholz1, F. Müller1,2, A.-D. Müller1,2, M. Hietschold1, I. Thurzo1, D. R. T. Zahn1, C. Pannemann3, and U. Hilleringmann3 — 1Institut für Physik, TU Chemnitz — 2Anfatec Instruments AG, Oelsnitz — 3Elektrotechnik und Informationstechnik, Universität Paderborn
Potentiometry with a Kelvin probe atomic force
microscope is used to investigate the contact resistances of pentacene
OFETs.
The potentiometry measurements are performed ex situ under
atmospheric conditions after storing the samples in air for several
weeks. At room temperature, the device performance is limited by the
resistance at the Au/pentacene injection contact, so that the mobility
in the channel region as deduced from potentiometry is about one order
of magnitude higher than the value obtained from the output
characteristics [1].
From two-dimensional device simulations in the accumulation regime, we
can deduce the hole mobility close to the interface between the active
channel and the SiO2 gate insulator. In the pinchoff regime, the
charge carriers are pushed away from the gate towards the interface
pentacene/air. The comparison between the device simulation and the
potentiometry traces reveals a larger mobility in this region of the
pentacene film. This finding indicates trap states at the
pentacene/SiO2 interface, probably related to adsorbed water
molecules.
[1] R. Scholz, A.-D. Müller, F. Müller, I. Thurzo, B. A. Paez, L. Mancera, D. R. T. Zahn, C. Pannemann, and U. Hilleringmann, Proc. of SPIE 5940 (2005), 59400I.