Self-Assembled in-Plane-Gate Thin-Film Transistors Gated by WOx Solid-State Electrolytes

Low-voltage WOx gated indium-zinc-oxide thin-film transistors (TFTs) with in-plane-gate structures are fabricated by using an extremely simplified one-shadow mask method at room temperature. The proton conductive WOx solid-state electrolyte is demonstrated to form an electric-double-layer (EDL) effect associated with a huge capacitance of 0.51 mu F/cm(2). The special EDL capacitance of the WOx electrolyte is also extended to novel in-plane-gate structure TFTs as the gate dielectric, reducing the operating voltage to 1.8 V. Such TFTs operate at n-type depletion mode with a threshold voltage of -0.5 V, saturation electron mobility of 13.2 cm(2)/V.s, ON/OFF ratio of 1.7 x 10(6), subthreshold swing of 110 mV/dec, and low leakage current less than 7 nA. The hysteresis window of the transfer curves is also explained by an unique reaction within the WOx electrolyte.