相变光透射特性具有窗口结构的VO_2薄膜

Phase transition optical properties of VO_2 thin films with window form

利用无机溶胶凝胶法制备出具有优良热致相变光学特性的ＶＯ２薄膜，通过改变制备过程中的条件，发现在一定的制备参数下，可得到光透射特性具有窗口形状的热致相变薄膜，该类薄膜相变前后在６００～８５０ｎｍ范围出现显著透光度窗口状变化现象。利用ＸＲＤ、ＸＰＳ对相变光学特性具有窗口结构的薄膜和具有典型相变特性的薄膜进行对比分析，结果显示利用无机溶胶－凝胶法得到的薄膜表面没有衬底离子出现，衬底扩散离子主要存在于薄膜和衬底界面之间。通过对引起相变过程中光透射窗口状变化的原因进行讨论，得到薄膜在相变过程中出现透射光谱窗口状的变化是来源于Ｖ３＋和衬底扩散离子Ｎａ＋的共同作用。

VO2 thin films with good phase transition optical properties were prepared by inorganic sol-gel process. The optical transmittance spectra of some prepared VO2 thin films show obvious window-form change before and after phase transition in the range from 600nm to 850nm. The films with typical-form and with window-form phase transition transmittance spectra were analyzed by XRD and XPS. The result show that there is some difference of valence state of V ion and X ray diffraction peaks in the films, Na+ ion doesn′t present in the surface of the films and the NaxV2O5 was in between the surface and the substrate. By comparing phase transition transmittance spectra and the results of XPS and XRD, it was deduced that the phenomenon of phase transition transmittance spectra with window-form was induced by V3+ ion of film and Na+ ion of substrate.