[22p-S222-1~9] 21.1 Joint Session K

[22p-S222-5] Photo-induced top-gate effect in a-InGaZnO TFTs

〇Kazushige Takechi¹, Hiroshi Tanabe¹ (1.NLT Technologies, Ltd.)

Keywords:oxide-semiconductor thin-film transistor,top-gate effect,light illumination

We discuss the top-gate effect under 425nm-light illumination in a-InGaZnO TFTs having a transparent top-gate electrode. The dependence of bottom-gate transfer characteristics on top-gate voltage (Vtg) shows specific behavior under 425-nm light illumination. The subthreshold current under 425-nm light illumination, whose photon energy is smaller than the optical bandgap of a-InGaZnO, increases with increasing the magnitude of negative Vtg. This result suggests a possible application of a-InGaZnO TFTs to a photosensor that works by controlling Vtg.