SiO_2基底表面VO_2薄膜的生长模式及相变性能分析

Growth Mode of VO_2 Film on SiO_2 Substrate and Its Phase Transition Property

采用无机溶胶-凝胶法在二氧化硅基底上制备不同厚度的二氧化钒薄膜,通过X射线光电子能谱、X射线衍射和场发射扫描电子显微镜分析薄膜的化学组成和微观结构,并利用变温傅里叶变换红外光谱对薄膜在红外波段的相变性能进行检测。结果发现:薄膜均沿(110)晶面择优生长;随厚度增加,其结晶度提高,表面晶粒明显增大,大小分布越不均匀,并导致薄膜在红外波段的低温和高温透过率均降低,滞后温宽变窄,相变陡然性增强。

VO2 films with different thicknesses were deposited on SiO2 substrate by an inorganic sol-gel method. The variation of stoichiometry, crystalline structure and surface morphology of the films with thicknesses were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, respectively. Furthermore, the effects of the composition and microstructure on the phase transition property of the films were studied in the mid-infrared range. The results indicate that all the films exhibit a （110） preferred orientation; the crystallinity is enhanced, and the grain size is improved with broader distribution in the thicker films. Accordingly, the thicker films show reduced transmission before and after the phase transition, narrower hysteresis loop and larger transition slope.