采用浸渍提拉法工艺在印制有金电极的Al2O3基片上制备了TiO2薄膜,并对不同厚度及工作温度下TiO2薄膜的气敏性能作了研究。结果显示,当TiO2气敏薄膜的工作温度一定时,存在一个最佳厚度,在该厚度下TiO2薄膜对H2具有最佳的气敏响应;当TiO2薄膜的厚度一定时,TiO2薄膜存在一个最佳工作温度,在该温度下TiO2薄膜对H2的气敏响应最为灵敏。XPS测试表明.TiO2薄膜经过H2氛围后,薄膜中吸附氧含量降低。利用TiO2薄膜表面吸附氧与H2的反应、薄膜对H2的吸附与脱附理论、电子的迁移等过程较为合理地解释了TiO2薄膜对H2的气敏响应。
TiO2 sensing films were prepared by dip-coating TiO2 sol on Al2O3 substrate. Effect of thickness and working temperature on the sensitivity of TiO2 thin films was studied. The result indicated that the sensitivity of the films changed as the film thickness and working temperature varied,and there existed an optimal thickness and an optimal working temperature. XPS result indicated that the adsorbed oxygen would decrease when films were tested in hydrogen-containing environment. The sensitive mechanism of TiO2 films to the hydrogen was discussed. The reason for existing an optimal thickness and work temperature could be explained by reaction between adsorbed oxygen and hydrogen and absorption and desorption theory. Sensitivity of TiO2 films was also related to the electron transfer from the film surface to the electrodes.