Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 67: OLEDs and OFETs
HL 67.3: Vortrag
Mittwoch, 16. März 2011, 18:30–18:45, FOE Anorg
(contribution withdrawn) Stability of Polarization in Organic Ferroelectric Metal-Insulator-Semiconductor (MIS) Structures — •Rene Kalbitz1, Peter Frübing1, Reimund Gerhard1, and Martin Taylor2 — 1Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany — 2School of Electronic Engineering, Bangor University, Dean Street, Bangor Gwynedd, LL57 1UT, UK
Ferroelectric field effect transistors (FeFETs) offer the prospect of an organic-based memory device. Since the charge transport in such devices is confined to the interface between the insulator and the semiconductor, the focus of the present study was on the investigation of this region. Capacitance-voltage (C-V) measurements of all-organic MIS devices with poly(vinylideneflouride- trifluoroethylene) (P(VDF-TrFE)) as gate insulator and poly(3-hexylthiophene)(P3HT) as semiconductor were carried out. When the structure was driven into depletion, a positive flat-band voltage shift was observed arising from the change in polarization state of the ferroelectric insulator. When driven into accumulation, the polarization was reversed. It is shown that both polarization states are stable. However, negative charge trapped at the interface during the depletion cycle masks the negative shift in flat-band voltage expected during the sweep to accumulation voltages. Measurements on P(VDF-TrFE)/P3HT based FeFETs yield further evidence for fixed charges at the interface. Output characteristics suggest the injection of negative charges into the interface region when a depletion voltage is applied between source and gate contact.