Low-voltage-driven pentacene thin-film transistors with cross-linked poly(4-vinylphenol)/high-k Bi55b3O15 hybrid dielectric for phototransistor.

This paper describes the fabrication of pentacene thin-film transistors (TFTs) with an organic/ inorganic hybrid gate dielectric, consisting of cross-linked poly(4-vinylphenol) (PVP) and Bi5Nb3O15. A 300-nm-thick Bi5Nb3O15 dielectric film, grown at room temperature, exhibits a high dielectric constant (high-k) value of 40 but has an undesirable interface with organic semiconductors (OSC). To form better interfaces with OSC, a cross-linked PVP dielectric was stacked on the Bi5Nb3O15 dielectric. It is shown that, with the introduction of a hybrid dielectric, our devices not only can be operated at a low voltage ( 5 V) but also have improved electrical characteristics and photoresponse, including a field-effect mobility of 0.72 cm(2)/V.s, current sub-threshold slopes of 0.29 V/decade, and a photoresponse of 4.84 at a gate bias V-G = 0 V under 100 mW/cm(2) AM 1.5 illumination.