The influence of visible light on the gate bias instability of In–Ga–Zn–O thin film transistors

We investigated the effect of photon irradiation with various energies on the gate bias instability of indium–gallium–zinc oxide transistors. The illumination of red and green light on the transistor caused positive threshold voltage (Vth) shifts of 0.23 V and 0.18 V, respectively, while it did not affect the Vth value in blue light after a positive bias stress. However, the stability of transistors was deteriorated with increasing photon energy after a negative bias stress: negative Vth shifts for red (−0.23 V) and blue light (−3.7 V). This difference can be explained by the compensation effect of the electron carrier trapping and the creation of meta-stable donors via photon excitation.

► Gate bias instability of a-IGZO TFTs under visible lights (red, green, blue, white and dark).
► Investigating positive and negative gate bias instability effects systematically.
► Compensation effect of the electron carrier trapping and the creation of meta-stable donors via photon excitation.