POLYTHIOPHENE FIELD-EFFECT TRANSISTOR WITH POLYPYRROLE WORKED AS SOURCE AND DRAIN ELECTRODES

The field-effect transistor has been fabricated, where polythiophene works as a semiconductor and a couple of polypyrrole layers act as a source and/or a drain electrode. The modulation ratio of the channel current with gate voltages has reached ca. 10(5), which is the largest one among organic FETs. This large modulation has been attributed to the depression of the channel current at no gate bias. It has been elucidated that the depression is caused by the barrier against hole transport formed inside the polythiophene layer and near the interface with polypyrrole.