Electrical stability of solution-processed indium oxide thin-film transistors under illumination stress

We investigated the variation in the electrical characteristics of solution-processed indium oxide (In₂O₃) thin-film transistors (TFTs) under monochromatic illumination conditions at different wavelengths of 1240, 800, 600, 500, 400, and 350 nm. In our results, there was no discernible difference between the characteristics of the TFT measured in the dark state and those obtained under light illumination at the wavelengths of 1240 nm and 800 nm. On the other hand, the TFT performance was remarkably changed when light having a wavelength of 600 nm or less was illuminated. It is found that the photon energy, which causes the characteristic degradation in the solution-processed In₂O₃ TFTs, is much lower than the direct band gap energy of In₂O₃. Consequently, illumination-induced instability in the performance of solution-processed In₂O₃ TFTs can be explained with the transition phenomena of neutral oxygen vacancies to ionized ones in the In₂O₃ semiconductor film.