Sensing of Electrostatic Potential by Using Top-Gate Effect in Amorphous In-Ga-Zn-O Thin-Film Transistors

In this paper, we discuss a preliminary possibility for sensing of electrostatic potential by taking advantage of the coupling effect in double-gate amorphous In-Ga-Zn-O thin-film transistors (TFTs) (a-In-Ga-Zn-O TFTs), which we call the top-gate effect. The TFT sensing device responds to attaching and detaching charged dielectric materials to the device surface. Drain current of the TFT sensing device changes, depending on the polarity of the charge with a sensitivity of 50 nA/kV. Results discussed here may lead to the possibility for a 2-D active-matrix electrostatic potential sensor.