Low-temperature growth of epitaxial BaTiO3 thin films with significant electro-optic coefficients

Barium titanate (BaTiO3, BTO) thin films, with their exceptionally high Pockels coefficients, present a promising alternative to lithium niobate (LiNbO3, LN) for integrated photonic devices. BTO's compatibility with complementary metal–oxide–semiconductor (CMOS) technology further enhances its appeal, contingent on the development of low-temperature growth processes. This study investigates the impact of growth temperature on the electro-optic (EO) performance of BTO films, revealing a clear correlation between lower growth temperatures and reduced EO coefficients. Notably, BTO films grown at 400 °C maintain significant EO coefficients of approximately 51.6 pm/V. These findings underscore the potential of low-temperature grown BTO films for high-performance EO applications. By elucidating the relationship between growth temperature, crystallinity, and EO performance, this research provides critical guidelines for fabricating high-performing BTO films compatible with CMOS technology, facilitating the advancement of next-generation photonic devices.