Influence of the dielectric constant of a polyvinyl phenol insulator on the field-effect mobility of a pentacene-based thin-film transistor

The mobility of pentacene thin-film transistors (TFTs) is correlated with the dielectric properties of their insulators. We varied the dielectric properties of the poly(4-vinylphenol) insulators of such TFTs by changing the molar ratio of the prepolymer/cross-linking agent while keeping the surface potential of the insulator surface constant. It was found that the field-effect mobility of the pentacene TFTs increases with increases in the dielectric constant of the insulators. A small increase in the dielectric constant of the insulator (a 20% increase, 3.6-4.3) was found to result in a dramatic increase in the field-effect mobility of pentacene TFTs by a factor of 3 (0.26 to 0.81 cm(2)/V s). (C) 2005 American Institute of Physics.