Gate insulators and interface effects in organic thin-film transistors

This paper presents a detailed characterization of different thermosetting polymers to be used as gate dielectrics in organic thin-film transistors. Selected materials yield smooth films with good insulation properties and offer attractive processing conditions. Bottom-gate transistors were prepared using these dielectrics and compared to hybrid transistors with surface-treated SiO2 as the dielectric. Gate bias induced leakage and solvent effects were investigated by preparing metal/insulator/semiconductor devices. Poly(3-hexylthiophene) (P3HT) transistors with organic dielectrics exhibited higher channel conductivity and lower mobility values with respect to P3HT-hybrid transistors and pentacene transistors. The importance of dielectric/semiconductor interface was discussed by comparing the performances of pentacene and P3HT transistors produced on different dielectrics.