The microstructure, leakage current and dielectric behaviors of (Nd,Ti)-codoped BiFeO3 thin films: effect of deposited substrate

Abstract

(Nd,Ti)-codoped BiFeO3 (BNFTO) thin films have been prepared on LaNiO3 (LNO)/Si, indium tin oxide (ITO)-coated glass, and monocrystalline silicon (Si) substrates by metal organic decomposition combined with sequential layer annealing. The influences of the various substrates on crystal structure, surface and cross-sectional images, insulating and dielectric properties were mainly investigated. All the samples crystallize into the pure rhombohedral perovskite structure with different relative intensities of (l00) peaks. Compared with other two films, BNFTO on ITO/glass shows lower leakage current due to the dense microstructure with relatively small grains. The voltage shift degree of capacitance–voltage curve is not same for BNFTO on ITO/glass and LNO/Si, which can be ascribed to the different content of defect complexes in both samples. The memory window of BNFTO on Si is 1.4 V at the applied voltage of ±5 V. The values of the figure of merit are 7.3 and 9.5 for BNFTO on ITO/glass and LNO/Si substrates, respectively. These present findings suggest that the microstructure and dielectric property depend strongly on the using substrate.