Co/ATO复合薄膜的结构与电磁光特性

以低成本的无机盐SnCl2·2H2O、SbCl2和Co（NO3）2·9H2O为原料，采用溶胶-凝胶法与浸渍提拉技术成功地制备出Co掺杂的ATO（Sb掺杂SnO2）复合薄膜。利用XRD、SEM、四探针电阻仪、紫外-可见光分光光度计及振动样品磁强计（VSM）等测试方法对Co／ATO复合薄膜的结构与物性进行了表征与评价。结果表明：少量的Co掺杂ATO复合薄膜仍保持四方金红石结构，复合薄膜中的晶粒分布均匀，其晶粒尺寸分布为4-7nm；随着Co含量的增加，Co／ATO复合薄膜的电阻率呈现出先降低后提高，且当Co含量为0．5mol%时，Co／ATO复合薄膜的电阻率最低为5．6×10^-3Ω·cm；在400-700nm可见光范围内，平均透过率达到90％以上，其光学带隙在3．9-4．0eV之间，且随着Co含量的增加，可见光透过率和光学带隙呈下降趋势；Co含量为3．0mol％的ATO复合薄膜具有室温铁磁性，其矫顽力约为100 Oe，磁性根源主要归结为磁性原子与基体载流子相互作用的结果。

Propagation property of electromagnetic waves in fractal cantor photonic crystals

Two novel structures of fractal Cantor multilayer with defects are presented. The Optical transmission matrix method is used to calculate the transmittance and the reflectance. Compared with the general Cantor multilayer, these novel structures have wider stopbands and show super narrow bands in the middle of the wider stopbands, which can be used as super narrow bandpass filters. The pass band can be less than 0.6 nm near the infrared wavelength of 1530 nm when there is an embedded defect in the cantor multilayer. The optical transmission in the central wavelength is higher than 99 %, which means a very low insert loss. If there are three layers, three super narrow peaks can be found in the middle of the stopband. The central wavelengths are respectively 1232.4 nm, 1372.8 nm and 1538.3 nm. It is much better than other kinds of narrow band filters and it may be used in the optical communications.