Correlation Between Ferroelectric and Fluorescent Properties by Introducing Eu Atoms Into Strontium Bismuth Tantalate Films

Electrical and fluorescent properties of Sr-deficient strontium bismuth tantalate co-doped with excess-Bi and Eu atoms (BiEu-SBT) were investigated, in which the Eu/Bi ratio was changed between 0 and 0.1. BiEu-SBT were synthesized on Pt (200 nm)/Ti (50 nm)/SiO2/Si substrates by using Sr0.8Bi2.2Ta2O9 and Sr-0.8(Bi-2, Eu-0.2)Ta2O9 mixed precursor solutions with a concentration of 0.33 mol/kg, in which Sr concentration was fixed at 0.8. From X-ray diffraction analysis, the diffraction peaks from Aurivillius phases were observed in the synthesized BiEu-SBT as well as in pure SBT. In BiEu-SBT, the lattice parameters along a- and c-axes at the Eu/Bi ratio of 0.1 in comparison with those of 0 decreased approximately 0.27 and 0.19%, respectively. The remnant polarization (2Pr) values of the synthesized BiEu-SBT with Eu/Bi ratio of 0 and 0.1 were approximately 8.4 and 6.8 mu C/cm(2), respectively. From photoluminescence (PL) measurement at a wavelength of 615 nm as a function of Eu/Bi ratio, the PL intensity of the synthesized BiEu-SBT was proportional to the Eu/Bi ratio, whereas, the 2Pr values were slightly decreased by Eu-doping.