Polymer ferroelectrics are playing an increasingly active role in flexible memory application and wearable electronics. The relaxor ferroelectric dielectric, poly(vinylidene fluoride trifluorethylene (PVDF-TrFE), although vastly used in organic field-effect transistors (FETs), has issues with gate leakage current especially when the film thickness is below 500 nm. This work demonstrates a novel method of selective poling the dielectric layer. By using solution-processed 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) as the organic semiconductor, it is shown that textured poling of the PVDF-TrFE layer dramatically improves FET properties compared to unpoled or uniformly poled ferroelectric films. The texturing is achieved by first vertically poling the PVDF-TrFE film and then laterally poling the dielectric layer close to the gate electrode. TIPS-pentacene FETs show on/off ratios of 10 5 and hole mobilities of 1 cm 2 Vs −1 under ambient conditions with operating voltages well below −5 V. The electric field distribution in the dielectric layer is simulated by using finite difference time domain methods.
|Journal||Advanced Materials Interfaces|
|State||Published - Feb 22 2019|
Bibliographical noteFunding Information:
A.L. and S.G. conceived the project and designed all experiments. A.L. performed all device fabrication and electrical measurements. A.L. and S.G. interpreted the device and structural data. A.P. performed the electron microscopy measurements and X.H. helped with the interpretation of the electron microscopy images. F.S-S. and K.H. were involved with the TCAD simulations. J.E.A. synthesized the organic semiconductor. A.L. and S.G. wrote the manuscript, and all authors provided their input. The authors acknowledge the support of this work through the National Science Foundation under Grant No. ECCS-1707588. The authors acknowledge the University of Missouri Electron Microscopy Core Facility and its support through the Excellence in Electron Microscopy Award.
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- ferroelectric dielectric
- field-effect transistors
- organic semiconductor
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering