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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Ｅｇ减小．还讨论了引起折射率峰移动和禁带宽度Ｅｇ减小的原因．
(Pb, Ca) TiO3 ferroelectric thin films were prepared on Si (100) substrates by sol-gel method. The ellipsometry spectra were measured at energy range of 2.3 ~ 5.0eV and the thickness And the optical constant spectrum in this interval. It was found that the refractive index peak shifted to the low energy direction when the Pb ion was substituted by Ca ion. At the same time, the absorption of (Pb, Ca) TiO3 shifted to the low energy direction with the increase of Ca content. The width Eg decreases. The reason why the refractive index peak shifts and the forbidden band width Eg decreases is also discussed.