The Preparation And Characterization Of Indium Tin Oxide Films On Quartz Optical Fibers

Indium Tin Oxide (ITO) transparent conductive film is an n-type semiconductor with high transmittance in visible region and electrical conductivity. Quartz optical fibers coated by ITO films can obtain the property of good photo and electron conductivity, which extends its application in sensor fields. This paper prepared the ITO films deposited on quartz optical fibers with good adhesion and photoelectric property through a sol-gel process, and discussed the effect of technologies on adhesion and photoelectric property of ITO films. Meanwhile, the adhesion of ITO films under thermal shock and ultrasonic treatment was investigated. The main research is shown as follows:Firstly, this paper discussed the effect of technologies on adhesion,transmittance in visible region and resistivity of ITO films to optimize the deposition technologies. The preparation technology of ITO films coated on quartz glass plane by a sol-gel method is relatively mature. However, it is hard to deposit the ITO films on the cylindrical surface of quartz optical fiber with strong bonding strength. It is worth noting that: ITO film is coated on the fibers with modification; the films is annealed at 500℃in muffle furnace for 70min; each layer is treated by ultrasonic wave with deionized water for 10s; the number of layers is four.Secondly, the method of thermal shock studied the adhesion between ITO film and fiber, and the morphology, resistivity, transmittance in visible region of ITO films and the photo conductivity of optical fibers with different quenching temperature was observed. The results indicated that when the quenching temperature less than 500℃, ITO films show as ductile material; when over 500℃, ITO films show as brittle material, and micro-cracks expand rapidly with the temperature increases; the critical failure point under thermal shock of ITO films is 200℃.Finally, the method of ultrasonic treatment studied the adhesion between ITO films and fiber, and the morphology, resistivity, transmittance in visible region of ITO films and the photo conductivity of optical fibers with ultrasonic treatment for different time was observed. From the cross-section morphology of ITO films with ultrasonic treatment, we can know that the micro-crack expand between 16min and 20min, but when time over 4min, the resistivity increase with the treatment time. We can conclude that the critical failure point under ultrasonic treatment of ITO films is 4min.Based on the results of experiment, the paper discussed the trends of ITO films performance combined with the vast literature reports in more depth, and provided the experimental and theoretical foundation for ITO films preparation and characterization in the future.