Low-voltage-driven pentacene thin-film transistors with cross-linked poly(4-vinylphenol)/high-k bi ₅Nb ₃O ₁₅ hybrid dielectric for phototransistor

This paper describes the fabrication of pentacenethin-film transistors (TFTs) with an organic/inorganic hybrid gate dielectric, consisting of cross-linked poly(4-vinylphenol) (PVP) and Bi ₅Nb ₃O ₁₅. A 300-nm-thick Bi ₅Nb ₃O ₁₅ 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 Bi ₅Nb ₃O ₁₅ 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/Vs, 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.