Influence of Temperature on the Illumination Time Dependent Photocurrent of Amorphous InZnO Thin-Film Transistors

The influence of temperature on the time dependent photocurrent (I _ph ) of amorphous InZnO (a-IZO) thin-film transistors (TFTs) under illumination with different wavelengths is investigated. Strong dependence of photocurrent on temperature is observed with the photocurrent follows the Arrhenius relationship. As the I _ph increases with the increasing illumination time, the activation energy (E _a ) of I _ph extracted from the Arrhenius plots shows two trends, with the E _a decreases firstly, and increases subsequently after a minimal value is reached. The decreasing and increasing trends suggest that the barrier lowering effect at the source side near the back channel and the screening effect of the accumulated photo-induced ionized oxygen vacancies within the channel region near the front channel are the dominating physical mechanisms of I _ph , respectively.