Synergistic optimization of oxygen stoichiometry and thermal annealing in ITO/Ag/ITO multilayer transparent conductive films for high-performance optoelectronic applications

ITO/Ag/ITO (IAI) multilayer transparent conductive films (TCFs) were fabricated by reactive magnetron sputtering under designed Ar/O 2 gas flow ratios and annealed up to 300 °C for 30 min in air. The results show that the optimized films with a 10 nm Ag interlayer, deposited under high appropriate oxygen flow (Ar/O 2 ∼30/2) and annealed at 300 °C for 30 min in air, achieved a sheet resistance of ∼7 Ω/sq. and >90% average visible transmittance (peak 90.3% at 550 nm with substrate included). X-ray reflectivity and diffraction revealed that annealing induces Ag and ITO crystallization, and interfacial smoothing, which results in improvements in conductivity and transparency. Moreover, the favorable optical constants of oxygen-rich ITO, which act as effective anti-reflection layers, are key factors for producing IAI TCFs with high transparency. These results demonstrate that synergistic control of oxygen stoichiometry and thermal annealing enables IAI TCFs to outperform conventional single-layer ITO, offering a promising route for high-performance transparent electrodes.