P‐16: Light‐Bias Induced Instability and Persistent Photoconductivity in In‐Zn‐O/Ga‐In‐Zn‐O Thin Film Transistors

Stress/recovery measurements demonstrate that even high‐performance passivated In‐Zn‐O/ Ga‐In‐Zn‐O thin film transistors with excellent in‐dark stability suffer from light‐bias induced threshold voltage shift (ΔV T ) and defect density changes. Visible light stress leads to ionisation of oxygen vacancy sites, causing persistent photoconductivity. This makes the material act as though it was n‐doped, always causing a negative threshold voltage shift under strong illumination, regardless of the magnitude and polarity of the gate bias.