Pentacene-based organic field-effect transistors with poly(methyl methacrylate) top-gate insulators fabricated by electrostatic spray deposition

Poly(methyl methacrylate) (PMMA) top-gate insulators were directly patterned via a shadow mask and deposited at room temperature on bottom-contact pentacene-based organic field-effect transistors (OFETs) by using electrostatic spray deposition (ESD). The drying process with high curing temperature to evaporate residual solvents was not required owing to the intermediate process between dry and wet processes. The top-gate OFET with a channel length of 5 μm exhibited superior electrical characteristics compared with the bottom-gate one based on the same pentacene active layer. The parasitic resistance of the top-gate OFET decreased significantly by reducing the thickness of the pentacene film. The successful implementation of the top-gate insulator formed by ESD is compatible with printed and flexible device fabrication technology.