Light Effects of the Amorphous Indium Gallium Zinc Oxide Thin-Film Transistor

The optical and electrical properties of the amorphous indium gallium zinc oxide thin-film transistor ($\alpha$-IGZO TFT) were studied. When the $\alpha$-IGZO TFT was illuminated at a wavelength of 660 nm, the off-state drain current slightly increased, while below 550 nm it increased significantly. The $\alpha$-IGZO TFT was found to be extremely sensitive, with deep-level defects at approximately 2.25 eV near the midgap. After UV light illumination, a slight change occurred on the surface of the $\alpha$-IGZO films, such as in terms of the oxygen 1s spectra, resistivity, and carrier concentrations. It is believed that these results will provide information regarding the photo-induced behaviors in the $\alpha$-IGZO films.