Investigations of enhanced device characteristics in pentacene-based field effect transistors with sol-gel interfacial layer

Pentacene films grown on sol-gel silica dielectrics showed a significant enhancement in field effect mobility, threshold voltages, and subthreshold swings. This letter investigates the contributing factors for the enhanced device characteristics. The smoother and more hydrophobic film surfaces of sol-gel silica (rms roughness of similar to 1.9 A and water contact angle of similar to 75 degrees) induced larger pentacene grains, yielding mobilities in excess of similar to 1 cm(2)/V s at an operating voltage of -20 V. Different sol-gel silica film thicknesses showed similar trends in improved performances, indicating that this phenomenon is clearly a semiconductor-dielectric interface phenomenon rather than a bulk dielectric effect. (c) 2007 American Institute of Physics.