Berlin 2005 – wissenschaftliches Programm
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SYOO: Organic Optoelectronics and Photonics
SYOO 6: Poster
SYOO 6.31: Poster
Montag, 7. März 2005, 18:00–20:00, Poster TU A
Dependence of poly-3hexylthiophene Electrical Properties on Residual Doping — •A. Herasimovich1, S. Janietz2, S. Scheinert1, and I. Hörselmann1 — 1Festkörperelektronik, TU Ilmenau, 98693 Ilmenau — 2Fraunhofer-Institut für Angewandte Polymerforschung (IAP), 14476 Golm
Field effect transistors (FET) and MOS capacitors have been prepared with different poly-3-hexylthiophenes (P3HT). The purity of the organic active layer and the controlled doping level are important parameters for the production of stable FET. We have investigated electrical properties of the devices with active layers made from unpurified, purified and intentionally doped P3HT, which are prepared by spin coating on n+-Si/SiO2 substrates. The measuring results of the capacitors from impedance spectroscopy and the data obtained for the FET show the following results: (i) Devices prepared from purified P3HT have a low residual doping of about 1016 cm−3 compared to the unpurified material with a doping level of about 1017 cm−3, (ii) controlled doping results in a concentration of about 3 × 1016 cm−3, (iii) the devices made from purified and doped materials show smaller hysteresis effects in comparison to the ones prepared from unpurified P3HT, (iv) the lateral mobility in devices with a HMDS treated oxide increases from 2 × 10−4 cm2/Vs for the purified material, up to 10−3 cm2/Vs for the unpurified one. Controlled doping results in a value of about 7 × 10−4 cm2/Vs.