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Hybrid Nanodielectrics for Low-Voltage Organic Electronics



Nanoscale hybrid dielectrics composed of an ultra-thin polymeric low-κ bottom layer and an ultra-thin high-κ oxide top layer, with high dielectric strength and capacitances up to 0.25 μFcm−2, compatible with low-voltage, low-power, organic electronic circuits are demonstrated. An efficient and reliable fabrication process, with 100% yield achieved on lab-scale arrays, is demonstrated by means of pulsed laser deposition (PLD) for the fast growth of the oxide layer. With this strategy, high capacitance top gate (TG), n-type and p-type organic field effect transistors (OFETs) with high mobility, low leakage currents, and low subthreshold slopes are realized and employed in complementary-like inverters, exhibiting ideal switching for supply voltages as low as 2 V. Importantly, the hybrid double-layer allows for a neat decoupling between the need for a high capacitance, guaranteed by the nanoscale thickness of the double layer, and for an optimized semiconductor–dielectric interface, a crucial point in enabling high mobility OFETs, thanks to the low-κ polymeric dielectric layer in direct contact with the polymer semiconductor. It is shown that such decoupling can be achieved already with a polymer dielectric as thin as 10 nm when the top oxide is deposited by PLD. This paves the way for a very versatile implementation of the proposed approach for the scaling of the operating voltages of TG OFETs with very low level of dielectric leakage currents to the fabrication of low-voltage organic electronics with drastically reduced power consumption.