钛酸铅钡铁电薄膜的光学性能研究

Investigation on Optical Properties of Pb_(1-x)Ba_xTiO_3 Ferroelectric Thin Films

采用溶胶-凝胶工艺在石英衬底上制备了Pb1-xBaxTiO3(BPT,x=0～1)铁电薄膜。利用X-射线衍射(XRD)、原子力显微镜(AFM)和拉曼光谱(Raman)对薄膜的相变特性、晶粒尺寸、结构和表面形貌进行了表征。结果表明,在750℃的退火温度下,所有的样品都已经完全晶化为多晶钙钛矿结构,薄膜表面均匀致密。在x=0.4时,薄膜由铁电四方相结构转化为顺电立方相结构。采用紫外-可见分光光度计在200～1000nm波长范围内测试薄膜样品的光学透过率,并通过透射光谱计算了薄膜的光学带隙以及折射率和消光系数的色散关系。

Pb1-xBaxTiO3（ BPT,x =0-1） thin films were grown on quartz substrates by sol-gel process. The phase transition,crystal size,structure,and morphology of the as-grown thin films were investigated by XRD,AFM and Raman. The results showed that all samples annealed at 750 ℃ had a complete perovskite phase structure,and the films were homogeneous and crack-free. The structure phase transforms from ferroelectric tetragonal to paraelecteic cubic phase when x = 0. 4. The optical transmittance was measured by spectrophotometer in the wavelength range of 200-1000 nm. The refractive index and the dispersion relation of extinction coefficient and optical bandgap were calculated through transmission spectrum.