钛酸锶钡薄膜的制备及其光学特性研究

用溶胶–凝胶法在石英和Al2O3单晶衬底上沉积Ba0.65Sr0.35TiO3薄膜,应用XRD与SEM表征了BST薄膜的晶化行为和表面形貌。在700℃退火1 h的薄膜,其表面光滑、晶粒大小分布均匀、无裂缝、无针孔。应用双光束光度计,在200~1000 nm的波长范围测量了薄膜的透射光谱,并根据“包络法”理论计算薄膜的折射指数。结果表明,当波长从近红外范围(1 000 nm)降低到可见光范围(430 nm)时,薄膜的折射率从2.16增加至2.35,当波长降低到紫外范围时,薄膜的折射率迅速增加,在365 nm处n =2.67。实验还发现沉积在Al2O3衬底上的BST的能隙约为3.48 eV。

Preparation and Optical Properties of BST Thin Films by the Sol-gel Processing

The Ba0.65Sr0.35TiO3 thin films were prepared by sol-gel method on fused quartz and Al2O3 substrates. The structure and crystalline characterization were studied by XRD and SEM. The films annealed at 700℃ for 1 h in air crystallized to perovskite structure, and the grains were evenly distributed, indicating Ba0.65Sr0.35TiO3 thin film the sol-gel derived has a well-defined microstructure. The refractive index increases from 2.16 to 2.35 as wavelength decreases from near infrared range (1 000 nm) to visible range (430 nm). The energy gap of BST films deposited on Al2O3 substrate is found to be around 3.48eV of indirect-transition type.