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采用化学共沉淀法制备了Al质量分数分别为0%,7%,9%和11%的掺杂Zn(OH)2,以及固定Al质量分数为9%,掺入不同质量分数Sn的Zn(OH)2,经500,700和900℃退火后,得到ZnO粉末样品,利用浸渍提拉法在Al2O3陶瓷管表面覆膜,制成气敏元件。通过X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的晶体结构和表面形貌进行了表征,采用气敏测试系统对气敏元件的特性进行了检测。研究了Al-Sn共同掺杂对气敏性能的影响,并讨论了Al-Sn共同掺杂ZnO厚膜的气敏机理。实验结果表明:掺杂的ZnO厚膜表面呈疏松多孔结构,Al-Sn共同掺杂的ZnO气敏材料对丙酮具有很好的选择性。其中,Al质量分数为9%、Sn质量分数为3%掺杂的ZnO样品,在工作温度为75℃时,灵敏度可达12 792,响应时间和恢复时间分别为1和3 s。
Zn (OH) 2 with Al mass fraction of 0%, 7%, 9% and 11% were prepared by chemical coprecipitation, and Zn (OH) 2 with fixed Al content of 9% and Sn with different mass fractions OH) 2, annealed at 500, 700 and 900 ℃ to obtain a sample of ZnO powder, which was coated on the surface of Al2O3 ceramic tube by impregnation and pulling method to form a gas sensor. The crystal structure and surface morphology of the sample were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The gas sensing system was used to test the characteristics of the gas sensor. The influence of Al-Sn co-doping on gas-sensing properties was investigated. The gas-sensing mechanism of Al-Sn co-doped ZnO thick films was also discussed. The experimental results show that the surface of doped ZnO thick film has a loose porous structure, and the Al-Sn co-doped ZnO gas sensing material has good selectivity to acetone. Among them, ZnO samples doped with 9% Al and 3% Sn have sensitivity of 12 792 and response time of 1 and 3 s respectively at 75 ℃.