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以天然白云母的解理面为基底,采用无机溶胶-凝胶法在其表面制备不同厚度的VO2薄膜,并研究了厚度对VO2薄膜的微观结构和红外光学特性的影响。利用SEM、XRD等手段分析了薄膜的表面形貌和晶体结构,利用原位FTIR分析了VO2薄膜半导体-金属相变特性。结果表明,云母表面VO2薄膜室温下具有(011)择优生长取向,随着厚度增加,薄膜晶粒变大,表面致密。同时薄膜厚度直接影响到VO2薄膜相变前后的红外透过率和薄膜在半导体-金属相变过程中产生的透过率变化ΔTr,当厚度为120 nm时,薄膜具有最大的红外透过率变化为70.5%。随着薄膜厚度的增加,VO2薄膜晶粒增大导致热致相变过程中滞回温宽变小,相变过程更加陡然。
Based on the cleavage plane of natural muscovite, VO2 thin films with different thicknesses were prepared on the surface by inorganic sol-gel method. The effects of thickness on the microstructure and infrared optical properties of VO2 thin films were also studied. The surface morphology and crystal structure of the films were analyzed by means of SEM and XRD. The in-situ FTIR was used to analyze the semiconductor-metal phase transition characteristics of VO2 thin films. The results show that the (001) preferred orientation of VO2 thin films on mica surface at room temperature increases with the increase of thickness, and the grains grow larger and the surface is denser. At the same time, the film thickness directly affects the infrared transmittance of the VO2 film before and after the phase transition and the change of the transmittance ΔTr produced by the film during the semiconductor-metal phase transition. When the thickness is 120 nm, the film has the largest change of the infrared transmittance Is 70.5%. With the increase of the film thickness, the grain size of the VO2 thin film increases and the hysteresis width becomes smaller and the phase transition process becomes more abrupt.