Electrical and dielectric properties of Ce-doped Ba0.6Sr0.4TiO3 thin films

The dielectric and electrical characteristics of Ce-doped (Ba0.6Sr0.4)TiO3 (BST) thin films were investigated as a function of Ce content. Both atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis showed that increasing the Ce doping ratio causes the decrease in grain size while the surface remains smooth and crack-free. The dielectric properties of the Ce-doped BST films were found to be strongly dependent on the Ce content. The dielectric constant and dielectric loss of the BST films decreased with increasing Ce content. However, it was also found that, compared with undoped films, the increase of Ce content improves the leakage current characteristics. The improvement of the electrical properties of Ce-doped BST films may be related to the decrease in the concentration of oxygen vacancies. The figure of merit (FOM) reached the maximum value of 48.9 at the 1 mol% of Ce doping. The dielectric constant, loss factor, and tunability of the 1 mol% Ce-doped Ba0.6Sr0.4TiO3 thin films were 320, 0.011, and 46.3%, respectively.