Metal-organic pentacene derivative with well ordered morphology for the application of low voltage organic thin film transistors

Metal organic pentacene based low voltage organic thin film transistors with field effect mobility as large as 0.8 cm²/V^-1.s ^-1 and on/off current ratio larger than 10⁶ have been fabricated. Thin films deposited by evaporation at different deposition rate has different morphology which leads to a difference in transistor characteristics. The films with a deposition rate of 2A/sec has better morphology and also the transistor behavior. AFM (atomic force microscope) and STM (scanning tunneling microscope) were used to understand the morphology and ordering of the molecules on the silicon surface which helps the transistor to operate at low voltages. The results presented here show a strong correlation between molecular ordering and the need of well-ordered films for the performance of organic thin film transistors (OTFT's).