Thorough Elimination of Persistent Photoconduction in Amorphous InZnO Thin-Film Transistor via Dual-Gate Pulses
Hao Liu, Xiaoliang Zhou, Changhui Fan, Jie Chen, Lei Lü, Hang Zhou, Shengdong Zhang
Abstract
Amorphous InZnO (a-IZO) thin film transistors (TFT) are highly sensitive to green or shorter wavelength light, and can be applied as photosensors. Nonetheless, the application of a-IZO TFT as photosensor is hindered by its persistent photoconduction (PPC), which leads to severe threshold voltage shift and low response speed. Here, we show that the PPC in the a-IZO TFT cannot be thoroughly eliminated by single-gate positive pulses. The residual ionized oxygen vacancy (Vo <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ) per gate pulse would gradually accumulate over time, giving rise to an increment of PPC under long-term illumination. To tackle this issue, a dual-gate transistor architecture together with dual-gate pulses configuration is proposed. Due to a stronger gate controllability, the residual Vo <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> that lie in the middle of the IZO channel is reduced, and the PPC of a-IZO TFT is thoroughly eliminated.