In-plane dielectric properties of epitaxial Ba 0.7Sr 0.3TiO 3 thin films grown on GaAs for tunable device application

Abstract

We have epitaxially deposited ferroelectric Ba 0.7Sr 0.3TiO 3 (BST) thin films grown on GaAs substrate via SrTiO 3 buffer layer by laser molecular beam epitaxy. Structural characteristics of the heterostructure were measured by various techniques. The in-plane dielectric properties of the heteroepitaxial structure under different applying frequency were investigated from -190 to 90°C, indicating Curie temperature of the BST film to be around 52°C. At room temperature, the dielectric constant of the heterostructure under moderate dc bias field can be tuned by more than 30% and K factor used for frequency agile materials is found to be close to 8. Our results offer the possibility to combine frequency agile electronics of ferroelectric titanate with the high-performance microwave capabilities of GaAs for room temperature tunable device application. © 2012 American Institute of Physics.