Characterization of pentacene based organic thin film transistor using conductive carbon electrode

Abstract

Amorphous carbon films prepared by our experiments exhibited very low resistivity (< 1 mΩ·cm) and good conductivity without any dopant. So, we applied to the gate electrodes for organic thin film transistor (OTFTs). The conductive carbon film used as the electrodes has properties such as good adhesion to glass and plastic substrate, good physical properties for the lifetime of electrodes, good electrical properties, thermal stability and high transparency. In this work, we have fabricated organic thin film transistors (OTFTs) of a back gate structure using the pentacene active region on polyvinylphenol (PVP) as gate dielectric. We fabricated three different types of transistors using pentacene film grown on PVP gate dielectric with gate electrodes of N ++Si, Au, and conductive carbon (a-C) films. We investigated the current image property of two structures by using the SPM method and compared the topology with its current images, which were simultaneously obtained by scanning a 3 μm × 3 μm region. The current images of OTFT with the different gate electrodes have shown that the vertical leakage current flows along the pentacene grain edges. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.