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 350nm. 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 1240nm and 800nm. On the other hand, the TFT performance was remarkably changed when light having a wavelength of 600nm 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.