Ultralow-Voltage Electric-Double-Layer Oxide-Based Thin-Film Transistors with Faster Switching Response on Flexible Substrates

Phosphosilicate glass (PSG) electrolyte films are deposited by improving the content of phosphorus doping during plasma-enhanced chemical vapor deposition, and a fast electric-double-layer (EDL) polarization response of 100 kHz is measured. The mechanism of the fast polarization response and EDL formation are investigated in detail. By using PSG electrolyte films as gate dielectrics, indium-zinc-oxide (IZO) thin-film transistors (TFTs) are fabricated on flexible plastic substrates. Due to the huge EDL gate capacitance, such TFTs show only 0.8 V operation and excellent electrical performances with a large current on/off ratio of 10⁷, low subthreshold swing of 72 mV/decade and high field-effect mobility of 16.76 cm²/V?s. More importantly, the devices exhibit a fast switching response above 100 Hz. Our results demonstrate that such PSG gated TFTs take a great step for low-power flexible oxide electronics application.