Electric characteristics of organic thin-film transistors and logic circuits with a ferroelectric gate insulator

Abstract

Organic electronic devices using a pentacene have improved importantly in the last several years. We fabricated pentacene organic thin-film transistors (OTFTs) with dielectric SiO 2 and ferroelectric Pb(Zr 0.3,Ti 0.7)O 3 (PZT) gate insulators. The organic devices using SiO 2 and PZT films had the field-effect mobility of approximately 0.1 and 0.004 cm 2/V s, respectively. The drain current in the transfer curve of pentacene/PZT transistors showed a hysteresis behavior originated in a ferroelectric polarization switching. In order to investigate the polarization effect of PZT gate dielectrics in a logic circuit, the simple voltage inverter using SiO 2 and PZT films was fabricated and measured by an output–input measurement. The gain of inverter at the poling-down state was approximately 7.2 and it was three times larger than the value measured at the poling-up state.