Ce-doped bismuth ferrite thin films with improved electrical and functional properties

Bi1-xCexFeO3 (BCFO) thin film capacitors (x = 0 to 0.2) are fabricated on indium tin oxide coated corning glass substrate by chemical solution deposition method. X-ray diffraction results show a partial phase transition from rhombohedral to tetragonal structure induced in BCFO thin film having preferred (110) orientation with increase in Ce dopant concentration. Current density-field (J-E) characteristics indicate that the leakage current density reduces by several orders of magnitude in Ce-doped BFO thin films resulting from smaller grain sizes and smoother surfaces. Space-charge-limited current and Fowler-Nordheim tunneling are identified as dominating leakage behavior in BCFO thin film capacitors at moderate and high field regions, respectively. Enhanced ferroelectric response with well-saturated (P-E) hysteresis loop is observed for Bi0.88Ce0.12FeO3 thin film having high remnant polarization (P (r)-127 A mu C/cm(2)) at an applied field of 1080 kV/cm. Bi0.88Ce0.12FeO3 thin film exhibiting well-defined capacitance-field (C-E) butterfly loop with dielectric loss (tan delta-0.03) measured at 10 kHz suggested good ferroelectric properties with high tunability of about 88 %.