Hysteresis-free organic field-effect transistors with high dielectric strength cross-linked polyacrylate copolymer as a gate insulator

Performance of organic field-effect transistors (OFETs) with polyacrylate (PA) copolymer cured at various temperatures as a gate insulator was studied. The chemical changes were monitored with FT-IR and the morphology and microstructure of the pentacene layer grown on PA dielectrics were investigated and correlated with OFET device performance. The PA thin film, which was cured at an optimized temperature, showed high dielectric strength (>7 MV/cm), low leakage current density (5 × 10−9 A/cm2 at 1 MV/cm) and negligible hysteresis in OFET. A field-effect mobility of ∼0.6 cm2/V s, on/off current ratio (Ion/Ioff) of ∼105 and inverse subthreshold slope (SS) as low as 1.22 V/dec were achieved. The high dielectric strength made it possible to scale down the thickness of dielectric, and low-voltage operation of −5 V was successfully realized.