Nature of Ohmic and Schottky contacts on pentacene-based organic field-effect transistor

Organic field-effect transistors (OFETs) have become promising components for a wide range of applications in the fast-growing field of organic electronics. Nevertheless, with the increasing need for high-performance OFETs, it is crucial to understand and challenge the contact resistance in these devices, because it represents a critical bottleneck that can significantly suppress the overall performance. Herein, we report the evaluation of the voltage dependence of the injection barrier in pentacene-based OFET devices with Au or Ag electrodes. The injection barrier of the device with Au electrodes showed an Ohmic nature with a barrier of approximately 170 similar to 200 meV, whereas the barrier in the device with Ag electrodes behaved as a Schottky contact and the zero-field injection barrier reached 552 +/- 2 meV.