Ferroelectric and Luminescent Properties of Eu-Doped SrBi₂Ta₂O₉ Films

Abstract

Sr-deficient and Bi-excess strontium bismuth tantalate (SBT) films doped with Eu atoms with concentrations from 1.25 to 5 mol % (SBT:Eu) were grown on Pt/Ti/SiO2/Si substrates by spin coating. The crystallinity of the SBT:Eu films was characterized by X-ray diffraction analysis. The ferroelectric and luminescent properties of the SBT:Eu films were measured at room temperature. Polycrystalline SBT:Eu films with the Aurivillius phase were grown, in which the Eu concentration was less than 5 mol %. The remnant polarization values of the 260-nm-thick SBT:Eu films with Eu concentrations of 1.25 and 5 mol % were approximately 4.0 and 0.86 µC/cm2, respectively. The PL intensity of the SBT:Eu films was significantly dependent on both annealing temperature and Eu concentrations. The maximum PL intensity was obtained in a 5 mol %-Eu-doped SBT film at an annealing temperature of 850 °C.