纳米晶LaFeO3 薄膜的制备与不同气氛处理后的光电子能谱

利用sol\|gel工艺, 在硅衬底上制备了纳米晶LaFeO₃薄膜. 测试了在乙醇蒸气和NO₂气氛下处理后的光电子能谱(XPS), 结果表明, 纳米晶LaFeO₃ 薄膜吸附乙醇后, 表面吸附氧含量明显降低, 铁含量略有下降; 吸附氧化性气体NO₂后, 表面吸附氧和铁含量明显增高, 且存在三价铁离子向四价铁离子转化的趋势. 通过测试和分析表明, LaFeO₃ 的敏感机理不仅与表面吸附氧相关, 还与表面三价铁离子的变价有关.

Preparation of Nanocrystalline LaFeO3 Film and XPS Studies on Nanocrystalline LaFeO3 Films Treated in Different Atmospheres

Nanocrystalline LaFeO_3 films were synthesized via the sol-gel technique on silicon substrate. XPS spectra were taken after the nanocrystalline LaFeO_3 films were treated in ethanol and nitrogen dioxide gases respectively. XPS analysis showed that when ethanol was adsorbed by LaFeO_3 film, the surface adsorption of oxygen obviously decreased, Fe content decreased a little bit as well; on the other hand, when NO_2 was adsorbed on its surface, the surface adsorbed oxygen increased apparently and Fe content increased as well; in the mean time, the transition trend from Fe 3+to Fe 4+was found. All the observations above show that the mechanism of the gas sensitivity of nanocrystalline LaFeO_3 films is closely related with the surface adsorption of oxygen and the changeable valance of iron.