Pentacene thin-film transistors with Al2O3+x gate dielectric films deposited on indium-tin-oxide glass

We report on the fabrication of pentacene thin-film transistors (TFTs) with Al2O3+x films as the gate dielectric that has been deposited on indium-tin-oxide glass by rf magnetron sputtering at room temperature. Although the Al2O3+x was expected to show lower capacitance and breakdown field than stoichiometric Al2O3, our pentacene TFTs with optimized thin Al2O3+x gate dielectric exhibited a moderately high field mobility of 0.14 cm2/V s, an outstanding subthreshold slope of 0.88 V/dec, and an on/off ratio over 106. Our work demonstrates that RT-deposited Al2O3+x is a promising gate dielectric material for organic TFTs.