Non-lead Ce: Na0.5Bi0.5TiO3-BiFeO3 solid solution thin film with significantly reduced leakage current and large polarization

The preferentially (100)-oriented 0.9Na(0.5)Bi(0.5)TiO(3)-0.1BiFeO(3) (NBT-BFO) solid solution thin films with and without Ce substitution were grown on a LaNiO3(100)/Si substrate via a metal organic decomposition method. The effects of Ce doping on the crystalline structure, leakage current and ferroelectric property of NBT-BFO thin film were investigated. The diffraction peaks of NBT-BFO shift to higher diffraction angle as a result of shrinkage in the unit-cell volume by Ce substitution. At higher electric fields, the NBT-BFO film presents Poole-Frenkel emission consistent with the high leakage current, whereas in the Ce-doped NBT-BFO film, the dominant mechanism is changed to space-charge-limited conduction, and the leakage current density is reduced by two orders of magnitude. Compared with rounded ferroelectric polarization hysteresis loops of NBT-BFO film, substantial enhancement of ferroelectricity has been achieved in Ce-doped NBT-BFO film, with a remanent polarization (P-r) of 32.3 mu C/cm(2). The capacitance voltage curves of Ce-doped NBT-BFO film show butterfly shape, and the degree of ferroelectricity is enhanced more and more with increasing applied voltage. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.