沉积温度对Na0.5Bi0.5TiO3铁电薄膜结构与性能的影响

Effect of Deposition Temperature on Structural and Properties of Na0.5Bi0.5TiO3 Ferroelectric Thin Films

利用脉冲激光沉积法和磁控溅射法在（001）SrTiO3单晶基片上构架了铁电异质结电容器Pt/La0.5Sr0.5CoO3/Na0.5Bi0.5TiO3/La0.5Sr0.5CoO3/SrTiO3（LSCO/NBT/LSCO/STO）。利用原子力显微镜（AFM）、X射线衍射仪（XRD）、铁电测试仪和压电力显微镜（PFM）研究了沉积温度对Na0.5Bi0.5TiO3（NBT）铁电薄膜的表面形貌、微结构和电学性能的影响。AFM结果表明,NBT薄膜晶粒尺寸随着沉积温度的增加先变小后增大。XRD结果显示,不同沉积温度下生长的NBT薄膜均为（00l）择优取向结构。铁电测试仪和PFM结果表明,NBT薄膜的铁电和压电性能随着沉积温度的增加先增大后减小,650℃生长的薄膜具有最高的剩余极化强度（19.6μC/cm^2）和最大的有效压电系数（146 pm/V）。

The Pt/La0.5Sr0.5CoO3/Na0.5Bi0.5TiO3/La0.5Sr0.5CoO3/SrTiO3（Pt/LSCO/NBT/LSCO/STO） heterostructures were fabricated on（001） Sr TiO3 substrates via RF magnetron sputtering and pulsed laser deposition. The impact of deposition temperature on the structure and electric properties of NBT thin films was investigated by atomic force microscopy（AFM）, X-ray diffraction（XRD）, ferroelectric test and piezoelectric force microscopy（PFM）, respectively. The results show that the grain size of NBT thin films first decreases and then increases with the increase of temperature. The XRD patterns indicate that all of the NBT films grown at different temperatures display the（00 l） preferred orientation. The ferroelectric and piezoelectric properties of NBT thin films both first increase and then decrease with increasing temperature. The film grown at 650 °C possesses the maximum remnant polarization（i.e., 19.6μC/cm^2） and effective piezoelectric coefficient（i.e., 146 pm/V）.