Operating Characteristics Measurements and Current Transport Mechanism Analysis of Semi-Conductive Al Gate Thin Film Transistor

Abstract

We have prepared vertical structure organic thin film transistors (VOTFTs). Compared with the thin film transistors in horizontal structure, VOTFTs can reduce the effect of interface states on the operating current. When negative voltage is applied on the drain/source electrode and gate/source electrode, we can get saturated I-V characteristics, which is similar to the MOSFET. The operating frequency is up to 20 kHz, and the switching speed rises to ton = 9.2 μs, toff = 9.6 μs, which show operating characteristic of high speed. When positive voltage is applied, unsaturated I-V characteristics are obtained. The gate voltage has strong control ability on channel current, and the operating current is up to 1.112 mA/cm2 with the low driving voltage. In the low voltage region, operating current of VOTFT is controlled by ohmic characteristic and space charge limited current (SCLC). In the high voltage region, it is controlled by SCLC with the exponential trap distribution.