Reducing the oxygen vacancy concentration in SrTiO3-δ thin films via an optimized O2 plasma treatment for enhancing device properties

[Display omitted] •Reduction of oxygen vacancy concentration in SrTiO3 thin films by O2 plasma treatment.•Defect control through a low-temperature process.•Changes in band gap and work function of SrTiO3 thin films by oxygen plasma treatment.•SrTiO3-based capacitor with an improved dielectric constant in the low-frequency region. Perovskite materials, specifically strontium titanate (SrTiO3, STO) thin films, have gained significant attention in materials science and electronics owing to their unique properties. However, low-temperature fabrication via sputtering can introduce oxygen vacancies that compromise film quality. O2 plasma treatment (OPT) has the potential to improve film properties, such as bond recomposition, electrical conductivity, and optical properties, by reducing the number of oxygen vacancies. In this study, STO films treated by O2 plasma were characterized using analytical techniques to understand the OPT-induced microstructural, morphological, and optical changes in these films. In addition, the possibility of improving device properties by low-temperature processes was confirmed by exploring the correlation between the number of oxygen vacancies reduced by the OPT process and the enhanced film properties. This result is expected to promote the application of STO thin films in flexible electronic devices and display components and provides insights into the role of oxygen vacancies and the effectiveness of OPT as a low-temperature solution for reducing their number.