Piezoelectric Pressure Sensing Device Using Top-Gate Effect of Dual-Gate a-IGZO TFT

We propose a pressure sensor composed of single-gate and dual-gate amorphous-indium-gallium-zinc-oxide thin-film transistors (TFTs) that are integrated with a P(VDF-TrFE)/PZT composite piezo-capacitor. The TFTs are connected in an inverter configuration, where the piezo-capacitor is connected to the floating top-gate of the dual-gate TFT (driving TFT). When the pressure is applied by finger pressing, the potential of the top-gate changes, and thus, the threshold voltage of the driving TFT shifts, leading to the generation of an output signal that is typically in the range of 200-300 mV.