Amorphous InGaZnO ultraviolet phototransistors with double-stack Ga ₂O₃/SiO₂ dielectric

This study investigates the electrical performance of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors with Ga₂O ₃ gate dielectric and applied on deep-ultraviolet phototransistors. To reduce the leakage current, we introduce the SiO₂ interlayer dielectric, which effectively reduces the off-current. Under the illumination of 250 nm, the measured responsivity of the device was 3.2 A/W at an applied gate bias of 0 V. The photo-generated carriers were injected into the channel by the applied electric field and Fowler-Nordheim tunneling. A large photocurrent and responsivity can be obtained which is attributed to the high mobility of the a-IGZO channel.