PLD Epitaxial Thin-Film BaTiO3 on MgO − Dielectric and Electro-Optic Properties

Abstract

The study demonstrates high-quality pulsed-laser-deposited (PLD) barium titanate (BTO) thin-films on a magnesium oxide substrate. The frequency response of the relative permittivity (dielectric constant) and the linear electro-optical coefficient (Pockels coefficient) are measured. At 0.2 GHz, the Pockels coefficient is fitted to be r42 ≈ 1030 pm V−1. It decreases to ≈390 pm V−1 at 10 GHz after which it remains constant up to 70 GHz. The unbiased BTO permittivity is measured to be εa ≈ 7600 at 0.2 GHz, dropping to ≈1100 at 67 GHz, while the biased BTO had a permittivity εa ≈ 2000 at 0.2 GHz, dropping to ≈500 at 67 GHz. These results fill an important experimental characterization gap for high-speed BTO applications and show the high quality of PLD-grown BTO films. Lastly, the material's crystalline quality is characterized and the domain distribution is imaged. The findings enable the design and fabrication of a new generation of BTO-based components for sensing and communications.