High Performance and Stability of Double-Gate Hf–In–Zn–O Thin-Film Transistors Under Illumination

Hafnium indium zinc oxide thin-film transistors (TFTs) with a double-gate structure were evaluated for the first time. Compared with devices with a single bottom gate, TFTs with an additional top gate exhibit improved subthreshold swing, threshold voltage, and field-effect mobility, as well as smaller subthreshold currents upon exposure to visible light. This phenomenon is attributed to the more effective suppression of excess photocurrents by the application of a double-gate structure. Negative-bias stress experiments under illumination indicate that the double-gate TFT exhibits very high stability compared with the device with a single-gate configuration.