Structural and electrical properties of Na0.5Bi4.0RE0.5Ti4O15 (RE=Tm, Yb and Lu) thin films

In the current study, a series of lanthanide ions, Tm, Yb and Lu, were used for doping at the Bi-site of the Aurivillius phase Na0.5Bi4.5Ti4O15 (NaBTi) to investigate the structural, electrical and ferroelectric properties of the thin films. In this regard, Na0.5Bi4.5Ti4O15 and the rare earth metal ion-doped Na0.5Bi4.0RE0.5i4O15 (RE=Tm, Yb and Lu, denoted by NaBTmTi, NaBYbTi, and NaBLuTi, respectively) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Formations of the Aurivillius phase orthorhombic structures for all the thin films were confirmed by X-ray diffraction and Raman spectroscopic studies. Based on the experimental results, the rare earth metal ion-doped Na0.5Bi4.0RE0.5Ti4O15 thin films exhibited a low leakage current and the improved ferroelectric properties. Among the thin films, the NaBLuTi thin film exhibited a low leakage current density of 6.96×10−7 A/cm2 at an applied electric field of 100 kV/cm and a large remnant polarization (2Pr) of 26.7 μC/cm2 at an applied electric field of 475 kV/cm.