Annealing Effects on ZrO ₂ Thin Films: Characterization and Gas Sensing Applications

This study investigates the effects of annealing on the structural, optical, and gas-sensing properties of ZrO ₂ thin films deposited by atomic layer deposition (ALD). The films were annealed in a nitrogen atmosphere at 700, 800, and 900 °C. Surface morphology, chemical composition, optical properties, and the film´s response to O2 were evaluated. Results showed that annealing improves surface homogeneity and oxygen sensitivity, highlighting the role of oxygen vacancies in gas sensing efficiency. Photoluminescence and cathodoluminescence spectra revealed that specific color centers, such as oxygen vacancies with trapped electrons, enhance the ZrO ₂ surface's sensitivity to oxygen. These findings emphasize the relationship between defect structures and material performance in gas sensing applications, offering insights for optimizing ZrO ₂ -based sensors.