Preparation And Electrical Performance Research Of Fluorine-doped Tin Oxide Thin Films

Transparent conductive films have been researched widely due to their goodperformance of light transmittance and conductivity. The most widely studiedtransparent conductive film is metal oxide thin films at present. There is a greatdiversity of transparent conductive films based on tin dioxide, such as ITO(IndiumTin Oxide)、FTO(Fluorine-doped Tin Oxide)、ATO(Antimony Tin Oxide) especially.For FTO, it was widely used in many areas because of its low cost, superiorperformance and simple preparation process, especially in electrochemical fields.Fluorine-doping tin dioxide sol were prepared by sol-gel hydrothermal methodin this paper. The sol was turn to the transparent conductive thin film by using spincoater. The optimum preparation condition was found by analyzed the temperature ofcrystal transformation. We discussed the influence of the concentration of the sol andthe ratio of F/Sn on the performance of transparent conductive film by using thecharacterization methods of X-ray diffractometer, scanning electron microscope,transmission electron microscope, ultraviolet and visible spectrophotometer, infraredradiation, differential thermal and thermogravimetric analyzer, Hall effectmeasurement.The results show that the size of the tin dioxide crystal is about10nm. The Fion has slight effect on the tin dioxide crystal. The film surface is flat and level, it hasno flaw, and the film and glass combine well, it has no flaw, and the thickness of thefilm is about3μm. The Hall test shows that the carrier concentration will increasewith the increase of doped fluorine, and the variation of mobility is opposite whichshows decreasing trend. Sheet resistance of transparent conductive film reachesminimum,185/□, when the ratio of F/Sn is0.8. Transmittance is optimal whichcan reach90%when the ratio of F/Sn is0.1. The index ΦTCindicates the combination property of conduction and transmittance. It can get the maximum valuewhich is22.3×1015, when the ratio of F/Sn is0.2. Combining the heavy-dopingtheory, the doping concentration of thin film belongs to the category of heavy-dopingdegenerate semiconductor with high carrier concentration and low resistance.