ZnO-Bi_2O_3混合氧化物厚膜的结构和气敏性能

Structure and Gas-sensitive Properties of ZnO-Bi_2O_3 Mixed Thick Films

采用金属蒸气氧化的方法制备了针状ZnO和椭球形Bi2O3纳米颗粒作为气敏厚膜的原材料,其中得到的Bi2O3为δ相和β相的混合物.通过XRD和SEM分析了ZnO、Bi2O3 以及ZnO-Bi2O3混合物厚膜的物相和表面形貌,并测试了厚膜的电导和气敏性能.结果发现纯Bi2O3对乙醇和丙酮蒸气有一定的气敏性能,表现为P型导电;与纯ZnO相比,ZnO-Bi2O3 混合物厚膜对苯、甲苯和二甲苯的敏感度降低,这与厚膜晶粒尺寸增大、其晶界势垒高度增大有关,然而Bi2O3可能作为一种弱的催化剂提高了厚膜对乙醇和丙酮的敏感性能.

Needle-shaped ZnO and ellipsoid-shaped Bi2O3 nanoparticles, as raw materials of thick films, were prepared by metallic vapour oxidation, and the obtained Bi2O3 is a mixture of delta and,3 phases. The phase structure and surface morphology of the thick films based on ZnO, Bi2O3 and ZnO-Bi2O3 mixture were investigated by XRD and SEM, then the resistance and gas sensitivity of the thick films were measured. The results indicate that Bi2O3 films show P-type conductivity and have sensitivity to alcohol and acetone more or less. Compared with ZnO, the sensitivity of ZnO-Bi2O3 to benzene, toluene and xylene is lower, which is relative with the increase of granular sizes and barrier height located at grain boundaries of the thick films. But Bi2O3, maybe as a very low activity catalyst, improves the gas sensitivity of the thick films to alcohol and acetone.