Abstract
Perovskite-type BaTiO3/SrTiO3 (BTO/STO) artificial superlattices were fabricated by molecular beam epitaxy process and their dielectric properties and refractive indices were measured. A large leakage current was observed in the films on Nb-doped STO substrate. Dielectric permittivity was therefore measured using planer interdigital electrodes. Fine planer electrodes were necessary to reduce the penetration of electric flux into the substrate. Interdigital electrodes were formed by electron-beam lithography. Dielectric permittivity of superlattices along the film surface was determined using electromagnetic field analysis. It was found that the dielectric permittivity of the BTO/STO superlattice with the period of 10 unit cells showed a maximum value above 30,000, which was almost independent from frequency up to 110 MHz. The refractive index of superlattices measured with a spectroscopic ellipsometer also showed the highest value when the period was 10 unit cells. This indicated that the structure of superlattices affected not only the ionic polarization but also the electric polarization. The origin of anomalous properties observed in superlattices may be interpreted by the strains induced into the film.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call