Low-Voltage Organic Field-Effect Transistor With PMMA/ZrO₂ Bilayer Dielectric

This paper reports on the application of a bilayer polymethylmethacrylate (PMMA)/ZrO2dielectric in copper ph-thalocyanine (CuPc) organic field-effect transistors (OFETs). By depositing a PMMA layer on ZrO2, the leakage of the dielectric is reduced by one order of magnitude compared to single- layer ZrO2. A high-quality interface is obtained between the organic semiconductor and the combined insulators. By integrating the advantages of polymer and high-fe dielectrics, the device achieves both high mobility and low threshold voltage. The typical field-effect mobility, threshold voltage, on/off current ratio, and subthreshold slope of OFETs with bilayer dielectric are 5.6 times 10-2cm2/V ldr s, 0.8 V, 1.2 times 103, and 2.1 V/dec, respectively. By using the bilayer dielectrics, the hysteresis observed in the devices with single-layer ZrO2is no longer present.