| SrFeO3-( is a new kind of oxygen sensing materials. In this work, SrFeO3-( thin films on Al2O3 substrate were prepared by sol-gel route. Sr(NO3)2 and Fe(NO3)3, were mixed in the atomic ratio Sr:Fe of 1:1 and dissolved in the water together with citric as a chelating agent. Al2O3 substrate was immersed into the sol and withdrew at rate of 4?cm/min, dried at room temperature and then sintered at 800℃ for 60?min. The process was repeated to obtain 6,7,8,11,15,17 layer films and the final heat treatment was performed at 900℃ in air atmosphere. The synthesized products have been characterized by structural (XRD, SEM) and thermal (DTA/TG) analyses.The effects of sintering temperature and dipping-coating times on properties of the film were also studied. SrFeO3-( microcrystalline powders were obtained by thermal treatment at 900℃ for 1 h in air. The oxygen sensitivity of different layer films has been measured in the temperature range of 377～527℃ under different oxygen or hydrogen concentration. It was found that optimum-dipping time is 11 times. SrFeO3-δ thin film showed p-type conduction in low temperature (T<700K). When the temperature rised (T≥750K). The p-n conduction changing point appeared. Through the addition of Co2+ or Cu2+ ions, the oxygen sensitivity of thin films was improved. In addition, double acceptor dopants (Fe3+ and Co2+) were studied to improve the oxygen sensitivity of SrTiO3. The results show that double acceptor dopants have some effect on electric properties, decreasing electric resistance and improving oxygen sensitivity. The photograph of different thin films was observed by means of SEM. With Fe3+ concentration increasing, there were many small holes on the Strontium Titanate thin film surface.
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