Indium zinc oxide (IZO) thin film for enhanced NO2 gas sensing using 532 nm laser annealing

This study investigated the effects of 532 nm laser annealing on indium zinc oxide (IZO) thin films prepared by RF sputtering using a composite target composed of 90 % In 2 O 3 and 10 % ZnO. The films were annealed at laser powers ranging from 2 W to 6 W, allowing effective thermal treatment of the thin films without damaging the substrate by precisely controlling the laser energy. The structural, morphological, and compositional properties were analyzed using XRD, SEM, AFM, XPS, and TEM. NO 2 gas sensing tests indicated that the film annealed at 4 W exhibited the best sensing performance, achieving a response value of 147.8 % at 1 ppm NO 2 concentration and an optimal operating temperature of 175 °C. These results demonstrate that laser annealing effectively promotes grain growth, defect modulation, and oxygen vacancy formation, thereby significantly enhancing the gas-sensing performance of IZO thin films. • Indium zinc oxide (IZO) thin films were fabricated via RF sputtering using a composite In 2 O 3 –ZnO target. • 532 nm laser annealing was applied at 2–6 W to tune film crystallinity, roughness, and grain size. • Optimal annealing at 4 W yielded minimal grain size (13.2 nm) and smoothest surface (8.6 nm). • NO 2 sensing at 175 °C achieved 147.8 % response at 1 ppm, with rapid response/recovery times. • Laser annealing enhanced adsorbed oxygen and defect states, improving sensitivity and selectivity.