溶胶-凝胶法制备SiO_2-TiO_2纳米复合薄膜紫外光处理的研究

UV Light Irradiation of Nanocomposite SiO_2-TiO_2 Thin Films Derived by a Sol-Gel Method

采用溶胶－凝胶技术，结合二步水解法分别在单晶硅片、石英玻璃和Ｋｇ玻璃上制备ＳiＯ2、ＴiＯ2纳米复合薄膜，采用高压汞灯对其进行紫外光处理，分别用ＡＦＭ、椭偏仪、ＦＴＩＲ、ＵＶ－Ｖis分光光度计以及ＸＲＤ对凝胶膜紫外光处理前后的光学性能和结构进行研究，并与传统的热处理进行比较与分析．研究表明，紫外光处理是实现凝胶膜低温致密化的有效方法之一，其致密化的机理不同于传统的热处理，主要是通过紫外高能光子诱导复合薄膜网络结构的原子中的电子激发，导致原子化学键的断裂，进而产生结构重组而致密化．

The nanocomposite silica-titania thin films were deposited with a dip-coating method on silicon wafers, fused quartz and K9 glass substrates from a sol made by a two-step hydrolysis method. A high-pressure mercury lamp was used to act as irradiation treatment. AFM, ellipsometry, FTIR, UV-Vis spectrophotometer and XRD were used to characterize the structure and optical properties of the as-grown and UV irradiated films. The results show that the UV-irradiation is one of the effective methods to densify the sol-gel thin films at a relative low temperature. The densification mechanism is different from that of the conventional thermal treatment. Electron excitation is induced directly by the UV light irradiation which is able to cause the bond cleavage in gel network and make gel films densify through the rearrangement of the gel structure eventually.