Low-temperature sol-gel processed AlO gate dielectric buffer layer for improved performance in pentacene-based OFETs

An approach to achieve improved performance in pentacene-based organic field effect transistors (OFETs) using high-k AlO prepared by a low temperature sol-gel technique as a thin buffer layer on a SiO gate dielectric was demonstrated. The maximum processing temperature for the AlO thin layer was 150 °C. The resulting all-inorganic SiO/AlO bilayer gate dielectric system exhibited a low leakage current density <1 × 10 A cm under an applied electric field strength of 1.8 MV cm, a smooth surface with an rms of 0.11 nm and an equivalent dielectric constant (k) of 4.13. The OFET fabricated as a result of this surface modification exhibited a significantly improved field effect mobility of 0.81 cm V s when compared with a reference device with a SiO single layer gate dielectric, which had a lower mobility of 0.28 cm V s.