Accelerating Photo-Response of InZnO TFTs via Field Modulation Under Dual-Gate Bias

Oxide-based photo thin-film transistors (TFTs) usually exhibit high photo-responsivity but suffer from slow dynamic photo-response. In this work, the accelerated photo-response in InZnO TFTs under dual-gate bias is demonstrated by biasing the bottom-gate close to turn-on voltage and using a thick bottom-gate insulator. The acceleration is attributed to the reduction of the vertical electrical field across the channel layer, which facilitates the recombination of ionized oxygen vacancies (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VO^²+</i>) with photo-generated electrons. As a result, a record-fast photocurrent rise time of about 10 μs is achieved under 409 nm illumination at an intensity of 2 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.