用溶胶凝胶法在Si(100)衬底上制备了(Pb,Ca)TiO3 铁电薄膜样品, 测量了其在2.3～5.0eV能量范围的椭偏光谱, 并获得样品的膜厚和在该区间的光学常数谱. 实验发现Pb离子被Ca离子取代后, 折射率峰向低能方向移动; 同时随着Ca含量的增加, (Pb,Ca)TiO3 的吸收边向低能方向移动, 表明Ca离子取代Pb离子后, 禁带宽度 g减小. 还讨论了引起折射率峰移动和禁带宽度E g减小的原因.
Calcium-modified lead titanate thin films deposited on si(100) substrate were prepared by sol-gel processing. The ellipsometric spectra of the PCT ferroeclectric thin films were obtained in the spectral range of 2.3～5.0eV, and their optical constants(the refractive index n and the extinction coefficient k) were determined. It was found that the peaks of the refractive indexes of the PCT thin films shift to the low energy region, their absorption edges shift to lower energy with an increase in Ca doping, this suggests that the energy gap reduces after Ca ions occupied Pb ions sites. The reasons of these shifts were also discussed.
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