Improved Performance of Organic Thin Film Transistor with an Inorganic Oxide/Polymer Double-Layer Insulator

We employ the Ta₂O₅/PVP (poly-4-vinylphenol) double-layer gate insulator to improve the performance of pentacene thin-film transistors. It is found that the double-layer insulator has low leakage current, smooth surface and considerably high capacitance. Compared to Ta₂O₅ insulator layers, the device with the Ta₂O₅/PVP double-layer insulator exhibits an enhancement
of the field-effect mobility from 0.21 to 0.54cm²/Vs, and the decreasing threshold voltage from 4.38V to -2.5V. The results suggest that the Ta₂O₅/PVP double-layer insulator is a potential gate insulator for fabricating OTFTs with good electrical performance.