The strong continuous induction effect based on isotype heterojunction transistors with different polymer modifications

Abstract Organic thin film transistors (OTFTs) with a p-type pentacene/dioctylbenzothienobenzothiophene (C8BTBT) heterojunction have been fabricated. Insulating materials, including inorganic silicon oxide (SiO 2 ), three polymers of Poly (4-vinylphenol) (PVP), Polystyrene (PS) and Polymethylmethacrylate (PMMA) were used as either dielectrics or modification layers. Our experiment shows that the morphology of C8BTBT films is highly relevant with the selection of the modification layer, which is due to the different physical/chemical properties of these polymers. The morphology difference of C8BTBT film then leads the pentacene film morphologies deposited upon C8BTBT to change again. Such fact clearly shows a "insulator to first-semiconductor to second-semiconductor" continuous induction effect in our heterojunction OTFTs. Finally, it has been found the SiO 2 /PS double-layer insulator promotes the growth of the C8BTBT film and upper pentacene film. And a high mobility of 3.6 cm 2 /Vs for OTFTs with this dielectric and low cost copper (Cu) source/drain electrodes can be achieved.