Transistor and Circuit Operation of Complimentary Organic Thin Film Devices

Abstract

Organic thin-film transistors (OTFTs) have attracted much attention as next generation electronic devices because of cost reduction, flexibility, and small overhead on the environment. In this study we fabricated OTFTs using pentacene as an active material on a heavily doped, thermally oxidized silicon wafer. The silicon substrate acted the gate, and thermal oxide and parylene acted as the gate dielectrics. The devices fabricated at 70 {degree sign}C have the field-effect mobility of approximately 0.2 cm2/Vs, which is comparable to hydrogenated amorphous silicon TFTs. The surface potential between source electrode and drain electrode was measured by scanning Kelvin probe force microscopy. In order to investigate the Schottky barrier and threshold voltage characteristics of OTFTs, we inserted the complimentary gate electrode into the basic structure of OTFTs. The shift of threshold voltages and the decrease of barrier height were observed in the direction of positive complimentary gate voltage.