云母表面不同厚度VO_2薄膜的红外光学特性

Infrared optical properties of VO_2 films on muscovite substrate with different thickness

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。

The films of VO2 with different thickness were fabricated on the cleavage plane of nature muscovite by an inorganic sol-gel method,in order to inverstigate the dependence of the thinckness on microstructure and infrared optical properties of the VO2 films.SEM and XRD were adopted to detect the morphology crystal structure of the films.In situ FTIR was carried out to analyze the semiconductor-metal phase transition properties of the films.The results show that the prepared films are（011） oriented on muscovite substrate at room temperature.The films become more compact and the crystal grains become larger as the thickness increases.Meanwhile,thickness directly affects the infrared transmittance of the films in semiconductor and metal state,and the infrared transmittance switching（ΔTr） during the phase transitions.The 120 nm-thick VO2 film exhibits the most excellent infrared transmittance switching of 70.5%.When the film thickness increases,the larger crystal grains of the film induces that the hysteresis width of the VO2 films during the phase transition decreases and the sharpness of the phase transition increases.