Well-balanced hole and electron charge transport in an organic p-type-insulator-n-type layered sandwich structure

The proper functioning of p/n stacked ambipolar transistors relies on a harmonized flow of current through both holes and electrons. This balance is critical, given the substantial impact that efficient drain hole-current (IHole) and drain electron-current (IElectron) have on the performance of various application components. For instance, in light-emitting ambipolar devices, they enhance luminous efficiency, while in logic circuits, they contribute to improved noise margins and circuit operation accuracy. To achieve this balance, our study introduces a thin parylene interlayer inserted between the p/n junctions. This interlayer aims to induce a harmonized flow of IHole and IElectron, particularly by enhancing IHole in p/n stacked ambipolar transistors. In the case of the PTCDI-C13/parylene/DNTT transistor (PPD transistor) with the parylene interlayer, our investigation reveals a well-balanced polarity ratio of 1.08 : 1 between hole and electron currents flowing. Furthermore, we explored the application of a complementary-like inverter utilizing a PPD transistor as a pull-up device and a PTCDI-C13/DNTT transistor (PD transistor) as a pull-down transistor. This setup demonstrated improved noise margins and stable pull-up and pull-down operations, even under transient operation. The proper functioning of p/n stacked ambipolar transistors relies on a harmonized flow of current through both holes and electrons.