Pentacene TFT With Reduced Threshold Voltage Using PMMA-co-MAA/Sol-Gel-Derived $\hbox {TiO}_{2}$ Composite Insulator

We report improvements in the characteristics of pentacene thin-film transistors (TFTs) achieved by using a poly(methylmethacrylate-co-methacrylic acid) (PMMA-co-MAA)/sol-gel-derived TiO₂ composite insulator. The gate-leakage current of TFTs containing this insulator is comparable to that of devices composed of bare PMMA-co-MAA. The reduction in the threshold voltage is the most pronounced improvement observed herein (compared to the variations of other characteristic parameters). This can be explained by the negative surface potential of the sol-gel-derived TiO₂ film.