Analysis of the Short-Term Response in the Drain Current of a-IGZO TFT to Light Pulses

In this letter, the response in the drain current (
$\text{I}_\text{D})$
of the amorphous indium–gallium–zinc oxide thin-film transistors under positive-bias illumination stress is measured with respect to time in less than 5 s under light pulses with altering frequencies and duty ratios. The curves of
$\text{I}_\text{D}$
under the light pulses are affected by the different defect-reacting rates under illumination and in the dark. By taking the derivative of
$\text{I}_\text{D}$
, the trend of the change in the number of defects becomes clear. The total behavior of
$\text{I}_\text{D}$
in response to light pulses can be fairly predicted by the integral of the derivative terms with a correction factor of charge trapping.