Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster: Organic Semiconductors

CPP 24.33: Poster

Mittwoch, 28. März 2012, 11:00–13:00, Poster A

Effect of doping on bias stress behavior of organic thin-film transistors — •Moritz Hein, Alexander Zakhidov, Moritz Riede, and Karl Leo — IAPP, TU Dresden

During the last few years, organic thin-film transistors have taken many important steps on their way into the market. By now they already reached a performance level that allows contributions in first applications such as backplanes for E-Ink-displays. An important problem regarding is the stability of the transistors during permanent gate bias stress. If the transistor operates on constant voltages for a longer period of time, the current flow between source and drain electrode is continuously reduced. This reversible degradation is found to be caused by a transport of charge carriers from the accumulation channel into the dielectric of the transistor and depends on the energy levels of both the dielectric and semiconductor. Hence, we compare the bias-stress effect for different organic semiconductors with given transistor geometry and silicon dioxide as dielectric material. Also we investigate the behavior of the characteristic transistor parameters before and after the bias-stress treatment. For the example of the system MeO-TPD on silicon dioxide, we show how the amplitude of the bias-stress effects can be reduced by weak doping of the semiconductor and a thereby induced shift of the Fermi energy.