Electrode Effects of Organic Thin-Film Transistor with Top and Bottom Contact Configuration

Abstract

Organic semiconductors have several unique properties that are different from those of inorganic semiconductors. Therefore, in order to develop an organic transistor, it is important to investigate structural factors of a device that govern the operation mechanism. Recently, we have designed a new device structure of an organic field-effect transistor (FET) with a diagonal configuration of source and drain electrodes, named as the top and bottom contact (TBC) configuration. In this device structure, the source and drain electrodes are prepared individually; therefore, it is convenient to independently study electrode effects on FET properties. In this study, we have prepared a pentacene TBC-FET, and studied electric field effects on FET properties in relation to the electrode configuration. By controlling several factors for the bottom electrode, we have observed marked changes in FET properties. It was revealed that the observed phenomena were mainly due to a difference in carrier injection efficiency.