Regensburg 2007 – wissenschaftliches Programm

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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.94: Poster

Dienstag, 27. März 2007, 18:00–20:00, Poster B

Polyvinylalcohol Dielectrics in Metal-Insulator-Metal, Metal-Insulator-Semiconductor and Organic Field Effect Transistor Structures — •Martin Egginger¹, Mihai Irimia-Vladu², Reinhard Schwödiauer², Andreas Tanda³, Siegfried Bauer², and N. Serdar Sariciftci¹ — ¹LIOS, JK University Linz, Altenbergerstr. 69, 4040 Linz, Austria — ²Soft Matter Physics, JK University Linz, Altenbergerstr. 69, 4040 Linz, Austria — ³plastic electronic GmbH, Rappetsederweg 28, 4040 Linz, Austria

Hysteresis is a well known phenomenon in the electrical characteristics of organic field effect transitors (OFETs) using polyvinylalcohol (PVA) as dielectric material. It was already proposed that mobile ionic impurities in the PVA might be the reason for the observed hystersis effect. A side-product of PVA is sodium acetate (NaAc). Further cleaning the received PVA by dialysis, significantly removed NaAc in the as received PVA. In order to study the influence of the NaAc ions on the properties of PVA, measurements were performed with metal-insulator-metal (MIM), metal-insulator-semiconductor (MIS) and OFET structures with C60 as semiconductor. Comparing the transfer characteristic curves of OFETs using the *as received* PVA with the dialysis grade PVA shows a dramatic decrease of the hysteresis. With intentionally added impurities of NaAc into the dialysis grade PVA the hysteresis is observed again and is even enlarged. Measurements on OFETs correlate well with dielectric spectroscopy results on MIM and MIS structures, thereby demonstrating that hysteresis in PVA based OFETs is caused by ionic impurities.