Structural, ferroelectric and leakage current properties of Bi3.96Pr0.04Ti2.95Nb0.05O12 thin films

Abstract

Praseodymium and niobium-substituted bismuth titanate (Bi3.96Pr0.04Ti2.95Nb0.05O12, BPTNO) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a sol–gel technology. The effects of annealing temperature (500~800°C) on microstructure and electric properties of thin films were investigated. X-ray diffraction analysis shows that the BPTNO thin films have a bismuth-layered perovskite structure with preferred (117) orientation. The intensities of (117) peak increases with increasing annealing temperature. With the increase of annealing temperature from 500°C to 800°C, the grain size of BPTNO thin films increases. The highly (117)-oriented BPTNO thin films exhibits a high remnant polarization (2Pr) of 48μC/cm2 and a low coercive field (2Ec) of 110kV/cm, fatigue free characteristics up to >108 switching cycles. A small leakage current density (J) was 6.23×10−8A/cm2 at 200kV/cm. The leakage current mechanisms were controlled by Poole–Frenkel emission in the low electric field region and by Schottky emission in the high field region.