退火温度对纳米TiO2薄膜的乙醇气敏特性的影响

采用直流磁控反应溅射法分别在Al2O3陶瓷管和Si(111)基片上制备纳米TiO2薄膜.首先将样品置于马孚炉中,分别在500℃、700℃和1100℃下进行3小时退火处理,然后利用XRD测定各退火条件下TiO2薄膜的晶粒尺寸和晶型,并对样品的气体敏感特性进行测试.实验结果表明:薄膜的结构、晶粒尺寸、晶相和气敏特性随着退火温度的不同而变化,经过500℃×3小时退火后的TiO2薄膜(锐钛矿相)对乙醇蒸汽的灵敏度最高,响应(恢复)时间为2-3s,并具有很好的选择性,其最佳工作温度为280℃左右.最后讨论了薄膜的乙醇气敏机理.

Effect fo Annealing Temperature on the Ethanol Sensing Properties for the Nanosized TiO2 Thin Films

Nanosized TiO2 thin films were prepared by DC magnetron sputtering deposition on alumina tubes and silicon substrates.After deposition, films were annealed in muffle at 500℃, 700℃ and 1100℃, respectively. The relation between sensitivity and annealing temperatures were studied by XRD and gas sensing measurements. Experimental results indicated that the film structure, crystallite size,phase and gas sensing property varied with the annealing condition, and the sensitivity of the anatase phase samples which was annealed at 500℃ was the best with wonderful selectivity and shortest response(recover) time. The best operating temperature was 280℃. The mechanism of the gas sensing properties was discussed.