Characteristics of transparent ZnO-based thin-film transistors with high-k dielectric Gd₂O₃ gate insulators fabricated at room temperature

A full room-temperature-fabricated ZnO-based thin-film transistor (TFT) has been demonstrated in this study using a gate dielectric of gadolinium oxide (Gd₂O₃) thin films. This is the first report on the use of Gd₂O₃ films as the gate insulator for a metal-oxide-based TFT. The properties of ZnO and Gd₂O₃ films deposited by pulsed laser deposition (PLD) at room temperature have also been studied under different oxygen pressures. In the high-oxygen-pressure region, the resistivity of the ZnO films was predominated by carrier concentration, while it is controlled by carrier mobility in the low-oxygen-pressure region. The on/off current ratio, field-effect mobility, and subthreshold swing of gate voltage obtained were approximately 10⁵, 1.12 cm² V^-1 s^-1, and 0.4 V/decade, respectively.