Thermal stability of thin-film periodic IZO structures with gradient modulation of oxygen content across thickness

By periodically varying the oxygen content in the working gas during high-frequency magnetron sputtering of an In$_2$O$_3$-based target with a 10 wt.% ZnO additive (IZO), thin-film transparent periodic structures with high conductivity and gradient-modulated oxygen content across their thickness were fabricated. The thermal stability of the electrical properties of these structures was investigated through annealing in both vacuum and open atmospheric conditions. It was found that the resistance of the structures increased in both annealing scenarios. The study demonstrated that during atmospheric annealing, the resistance increase is primarily due to a reduction in the concentration of free electrons. This reduction is attributed to the neutralization of oxygen vacancy donor centers by atmospheric oxygen. In contrast, during vacuum annealing, the resistance increase is mainly caused by a decrease in electron mobility, resulting from the degradation of the modulated (gradient) structure of the film.