Low-voltage organic thin film transistors with hydrophobic aluminum nitride film as gate insulator

This paper reports on the low-voltage (<5 V) pentacene-based organic thin film transistors (OTFTs) with a hydrophobic aluminum nitride (AlN) gate-dielectric. In this work, a thin (about 50 nm), smooth (roughness about 0.18 nm) and low-leakage AlN gate dielectric is obtained and characterized. The AlN film is hydrophobic and the surface free energy is similar to the organic or the polymer films. The demonstrated AlN-OTFTs were operated at a low-voltage (3-5 V). A low-threshold voltage (-2 V) and an extremely low-subthreshold swing (∼170 mV/dec) were also obtained. Under low-voltage operating conditions, the on/off current ratio exceeded 10⁶, and the field effect mobility was mobility was 1.67 cm²/V s.