Velocity-field characteristics of polycrystalline pentacene field-effect transistors

In this article, we report on the carrier velocity of polycrystalline pentacene transistors as a function of lateral electric field in both quasistatic and nonquasistatic regimes. We performed a series of measurements on devices with a range of channel lengths. At moderate lateral electric fields (<5 X 10(5) V/cm), the characteristics are similar to those of disordered or amorphous organic semiconductors. The highest velocities we have measured are near 5 X 10(4) cm/s at room temperature. Additional dynamic measurements, using both step response and frequency response methods, correlate strongly to the quasistatic findings. These results fill an important void between experimental results that have been obtained with disordered/amorphous organic semiconductors and single crystals. (C) 2010 American Institute of Physics. [doi:10.1063/1.3374707]