Effects of Polymeric Dielectric Morphology on Pentacene Morphology and Organic TFT Characteristics

Rongbin Ye,Koji Ohta,Mamoru Baba,M Jawaid,El-R Kenawy

doi:10.1051/matecconf/20166704009

Abstract

In this paper, we report on the effects of the polymeric dielectric morphology on pentacene morphology and organic thin film transistor (TFT) characteristics. The morphology and thickness of cyclo-olefin polymer (COP) dielectric could be controlled by selecting a solvent. Higher the solvent’s boiling point is, thinner and smother COP films could be obtained. Using the solvent of trimethylcyclohexane, the spin-coated COP films of ca. 330 nm with the peak-to-valley of 7.35 nm and the roughness of root mean square of 0.58 nm were obtained, and pentacene TFT showed high mobility of 2.0 cm 2 V -1 s -1 , which originated from highly ordering of pentacene thin films deposited on the smoother and thinner COP films.

Highlights

Organic thin film transistors (OTFTs) offer a promising technology for low-cost and large-area electronic applications such as active-matrix displays, electronic papers, flexible microelectronics and chemical sensor arrays [1]
We report on the effects of the gate-dielectric morphology on pentacene morphology and OTFT characteristics
The morphology of the polymer dielectric could be controlled by various boiling point (BP) solvents

Summary

Introduction

Organic thin film transistors (OTFTs) offer a promising technology for low-cost and large-area electronic applications such as active-matrix displays, electronic papers, flexible microelectronics and chemical sensor arrays [1]. The surface treatments employed on inorganics would be practically impossible to use in top gate devices. Organic dielectrics offer the freedom to build both top and bottom gate devices more by the use of solution coating techniques and printing. Polymeric dielectrics have been considered as preferable gate dielectric materials due to their numerous advantages over inorganic materials: i.e., flexible, hydrophilic, easy process, and low cost. We have been studied low-k cyclo-olefin polymer (COP, ZEONEX 480R) as a gate dielectric [2]. It has been known that the surface energy of gate dielectrics strongly influences organic film morphology and device characteristics [3]. We report on the effects of the gate-dielectric morphology on pentacene morphology and OTFT characteristics. The morphology of the polymer dielectric could be controlled by various boiling point (BP) solvents

Experimental

Results and Discussions

Conclusions