椭偏光谱法研究溶胶-凝胶TiO2薄膜的光学常数

以钛酸丁酯为前驱体，采用溶胶-凝胶工艺成功制备了TiO₂薄膜.利用反射式椭圆偏振光谱仪测量了薄膜的椭偏参量Ψ和Δ，并用Cauchy模型对椭偏参数进行数据拟合，得到了薄膜的厚度和光学常数在380—800 nm的色散关系.用分光光度计测量了薄膜的反射率，并用干涉法计算薄膜的厚度；使用原子力显微镜观测了薄膜的表面微结构，分析讨论了不同退火温度处理的薄膜微结构与光学常数之间的关系.研究结果表明，Cauchy模型能较好地符合溶胶-凝胶TiO₂薄 关键词： 光学常数 2薄膜')" href="#">TiO₂薄膜 溶胶-凝胶 椭圆偏振

Optical constants of sol-gel derived TiO_2 films characterized by spectroscopic ellipsometry

Nanostructured titanium oxide films were deposited on silicon substrate via sol-gel dip coating method with tetrabutyl titanate as precursor. With reflective spectroscopic ellipsometry, the ellipsometric parameters ψ and △ of Ti_O2 films were measured.Then, with the Cauchy model, the ellipsometric data were fitted, and both the thickness and the optical constants at 380-800 nm wavelength of the films were obtained. A comparison was made between the reflectance of the films derived with the spectrophotometer and the simulated results. Meanwhile, the thickness of the films was calculated by interference method. Moreover, with the atomic force microscopy the surface microstructures of the films annealed at different temperatures were observed, and the relationship between the surface microstructures and optical constants of films was further discussed. The results showed' that Cauchy model works well in describing the dispersion relationship of the TiO_2 films, and the variation rules of optical constants (the refractive index, the extinction coefficient) with wavelength were obtained. The optical constants of the films were related with the microstructure. Those simulated reflectance spectrum accorded well with the measured result. And with a deviation of only 2.5 %, the calculated value of the thickness was in accordance with which was obtained by spectroscopic ellipsometry.