Ferroelectric and photoluminescence properties of (Ca, Eu)Bi₂Ta₂O₉ thin films prepared by pulsed laser deposition

Abstract

Thin films of CaBi₂Ta₂O₉ (CBT) and Eu³⁺ doped CaBi₂Ta₂O₉ (CEBT) were deposited on platinum-coated silicon substrates via the pulsed laser deposition technique. The microstructural, leakage current, ferroelectric behavior and photoluminescence properties of CBT/CEBT films were systematically studied. The CBT/CEBT films form single phase with a polycrystalline perovskite structure is confirmed by X-ray diffraction, and the CEBT films exhibit better crystallinity when doped with a number of Eu³⁺ ions. Meantime, the ferroelectric hysteresis loops show that enhanced ferroelectric property with a remnant polarization 2P_r = 8 μC/cm² are obtained from CEBT film when x = 0.15. Leakage current density curves show that the Eu³⁺ doping could lead to the increase of leakage current of CBT film. Furthermore, under the excitation of 394 nm and 464 nm light, the thin films exhibit yellow and red emission peaks centered at 592 nm and 613 nm, which attributes to the f–f electronic transition of ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ of Eu³⁺ ions. This study suggests that Eu³⁺ doped CaBi₂Ta₂O₉ films have a potential application in the new multifunctional photoluminescence ferroelectric thin-film devices.