Table of Contents
ISRN Condensed Matter Physics
Volume 2012 (2012), Article ID 313285, 7 pages
http://dx.doi.org/10.5402/2012/313285
Research Article

Pentacene Active Channel Layers Prepared by Spin-Coating and Vacuum Evaporation Using Soluble Precursors for OFET Applications

1Department of Electrical Engineering, Aichi Institute of Technology, Toyota City 470-0392, Japan
2School of Electrical Engineering, Inha University, 253 Yonghyun-gong, Nam-gu, Incheon 402-751, Republic of Korea

Received 30 August 2012; Accepted 15 September 2012

Academic Editors: V. Kochereshko and L. Pusztai

Copyright © 2012 Shizuyasu Ochiai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Pentacene OFETs of bottom-gate/bottom-contact were fabricated with three types of pentacene organic semiconductors and cross linked Poly(4-vinylphenol) or polycarbonate as gate dielectric layer. Two different processes were used to prepare the pentacene active channel layers: (1) spin-coating on dielectric layer using two different soluble pentacene precursors of SAP and DMP; (2) vacuum evaporation on PC insulator. X-ray diffraction studies revealed coexistence of thin film and bulk phase of pentacene from SAP and thin film phase of pentacene from DMP precursors. The field effect mobility of 0.031 cm2/Vs and threshold voltage of −12.5 V was obtained from OFETs fabricated from SAP precursor, however, the pentacene OFETs from DMP under same preparation yielded high mobility of 0.09 cm2/Vs and threshold value decreased to −5 V. It reflects that the mixed phase films had carrier mobilities inferior to films consisting solely of single phase. For comparison, we have also fabricated pentacene OFETs by vacuum evaporation on polycarbonate as the gate dielectric and obtained charge carrier mobilities as large as 0.62 cm2/Vs and threshold voltage of −8.5 V. We demonstrated that the spin-coated pentacene using soluble pentacene precursors could be alternative process technology for low cost, large area and low temperature fabrication of OFETs.