Vertically stacked hybrid organic–inorganic complementary inverters with low operating voltage on flexible substrates

Hybrid organic–inorganic complementary inverters were demonstrated on a flexible polyethersulfone (PES) substrate with vertically stacked p-channel pentacene and n-channel amorphous indium gallium zinc oxide thin-film transistors (TFT). Al2O3 layers grown by atomic layer deposition were used as top- and bottom-gate dielectric layers. Common-gate top-contact p- and bottom-contact n-channel TFTs showed saturation mobility values of 0.3 ± 0.02 and 5.3 ± 0.2 cm2/Vs and low threshold voltage values. Complementary inverters yielded high gain values of 61 V/V with high and balanced noise margins at a low supply voltage of 5 V. The independent control of the thickness of the gate dielectric layer used for each transistor in this proposed vertically stacked geometry, allows for the realization of high-density low-power complementary circuits with high gain and balanced noise margins.