Orientation of pentacene films using surface alignment layers and its influence on thin-film transistor characteristics

We have investigated the effect of surface order on the orientation and mobility of pentacene. The surface order was created using monolayers and polymers that are normally used to align liquid crystals. Rubbed polyvinylalcohol layers were found to align approximately 27% of the pentacene grains within a 30 degrees range. When introduced in a thin-film transistor, they were found to enhance the saturation current by a factor of 2.5. A mechanism for this enhancement is proposed. (C) 2001 American Institute of Physics.