文摘
The fabrication of low-voltage flexible organic thin film transistors using zirconia (ZrO2) dielectric layers prepared via supercritical fluid deposition was studied. Continuous, single-phase films of approximately 30 nm thick ZrO2 were grown on polyimide (PI)/aluminum (Al) substrates at 250 掳C via hydrolysis of tetrakis(2,2,6,6-tetramethyl-3,5-heptane-dionato) zirconium in supercritical carbon dioxide. This dielectric layer showed a high areal capacitance of 317 nF cm鈥? at 1 kHz and a low leakage current of 1.8 脳 10鈥? A cm鈥? at an applied voltage of 鈭? V. By using poly(3-hexylthiophene) (P3HT) as a semiconductor, we have fabricated flexible thin film transistors operating at VDS = 鈭?.5 V and VG in a range from 0.5 V to 鈭? V, with on/off ratios on the order of 1 脳 103 and mobility values higher than 0.1 cm2/(V s).
Keywords:
supercritical fluid deposition; zirconia; high-k; low voltage; organic transistors and polythiophene