Split-Gate Ambipolar Thin-Film Transistors and Circuits

Solution-processed ambipolar organic thin-film transistors (TFTs) offer great potential for simple and low-cost fabrication by means of easy-to-fabrication process and both n-type and p-type operation in a single device. Nevertheless, the DC-gain, noise margin, power consumption of ambipolar organic circuits suffer from the fact that always one of the transistors in the inverter cannot be switched off completely. Hence, the typical Z-shaped inerter characteristics is shown in ambipolar inverters. We present novel split-gate ambipolar TFTs architectures (co-planar with gate-gap, non-planar, and inverted non-planar split-gate TFTs) to operate as an either p-type or n-type device depending on the bias voltage at the secondary-gate for complementary circuitry. Non-planar split-gate TFTs with no gate-gap showed orders of magnitude higher performances compared to co-planar split-gate TFTs. We also present 2D numerical simulations for comprehensive understanding of different split-gate device structures. Finally, reconfigurable complementary logic circuits using split-gate were demonstrated for the first time.