纳米半导体材料SO4^2—／La—α—Fe2O3的表面结构与酒敏特性

The Surface Structure of Nano-semiconductor SO~ 2- _4/La-α-Fe_2O_3 and Sensitivity to Ethanol

对纳米半导体材料 SO2 -4/La-α-Fe2 O3 进行了 IR、XPS分析和比表面积测定实验 ,并制成厚膜型酒敏元件 ,探索了焙烧温度与灵敏度的关系以及气敏元件的稳定性。结果表明 ,样品中 SO2 -4与 La-α-Fe2 O3 表面的金属离子 (Fe3 + 或 La3 + )结合构型是无机桥式配位型 ,SO2 -4的加入使 Fe2 p3 /2 电子结合能从 71 0 .85 e V提高到 71 2 .1 0 e V,表面 Fe3 + 在 SO2 -4的作用下显示出更正的电位 ,从而改变了半导体性质 ,由 p型转变成为 n型 ;在焙烧温度为 45 0℃烧结的 SO2 -4/La-α-Fe2 O3 元件 ,对酒精的灵敏度最高 (S=3 5 .7)、稳定性好。

Nano semiconductive material SO 2- 4/La α Fe 2O 3 has been characterized by means of IR?XPS and specific surface area measurements. The ethanol sensors were fabricated with the nano powders . The results indicated that SO 2- 4 is combined with Fe 3+ of La α Fe 2O 3 through an inorganic bridge structure. Addition of SO 2- 4 makes the binding energy of Fe2 p 1/3 increased from 710 85 eV to 712 10 eV and Fe 3+ became more positive in charge, thus, the semicudutivity of La α Fe 2O 3 is changed from the p type into the n type. The sensor fabricated from SO 2- 4/La α Fe 2O 3, calcinated at 450 ℃ showed sensitivity of 35 7 to ethyl alcohol and good stability.