Preparation And CO₂ Sensitive Properties Of CuO-SrTiO₃ Composite Semiconductor Materials

With the development of modern society, people have realized that environment is very important to our lives. we have stopped exceeding exploiting and polluting, beginning to protect the nature and resources. CO₂ is the mainly part of hothouse effect, so the inventions which used to monitor and control the exhale gas come out.In the article, inorganic salts were used as raw materials of CuO-SrTiO₃ which prepared by sol-gel method. Research was made on the preparation of CuO-SrTiO₃ and its sensitivity. The analysis of FI-IR spectra, XRD patterns and SEM morphologies were used to analyze the effect of chelating agent, crystal grain, crystal phase and pattern of the films. Research was focused on different chelating agents, water bathing and sinter temperature to make eligible films. At last the results indicated that: the films prepared by citric acid as chelating agent, water bathed in 60oC, sintered at 750℃for 30min were eligible.The results indicated that the CuO-SrTiO₃ films had good resistance-temperature properties, and the sensitivity could get to 1.45 (6%CO₂).Different amounts of Na⁺ and La³⁺ were doped into the sol, in order to improve the sensitivity of the films. The results indicated that: when doped 3% Na⁺ or 3%La³⁺ the resistance fell down, the sensitivity could get to 1.55(3%Na⁺) or 1.49(3%La) at the atmosphere of 6%CO₂.The sensitivity of CuO-SrTiO₃ thin films was improved greatly by doping noble-metal Ag. The films were infiltrated into 1%mol/L AgNO₃ and sintered at 750℃for 30min, the sensitivity could get to 1.82 (6%CO₂).CuO-SrTiO₃ which doped 3% Na⁺ and sintered at 750oC was doped different materials to prepare sintered gas sensors. The results indicated that: glass material could improve the adhering between the sensitivity material with the substrate, but the resistance increased, the sensitivity could get to 1.32. The resistance could fell down by added Pt, but the sensitivity declined to 1.13.