Testing field and annealing temperature dependence of leakage properties in Bi3.25La0.75Ti3O12 thin films

Ferroelectric Bi3.25La0.75Ti3O12 thin films annealed at different temperatures were prepared on Pt/Ti/SiO2/Si substrates by metalorganic decomposition method. The leakage current behavior and the current conduction mechanism were investigated. For all films, the leakage current density − electric field (J−E) characteristic is confined within a “triangle” in the log (J)− log (E) plane bounded by three limiting curves: Ohm's law (J ∝ E), trap-filled-limit (J ∝ Ea, a > 1), and Child's law (J ∝ E2). At high field region, Bi3.25La0.75Ti3O12 thin films with grains of rod-like show higher leakage current, while films with grains of spherical- or planar-like exhibit lower leakage current.