掺杂ZnO厚膜对丙酮气敏特性的影响

Effects of Doped ZnO Thick Films on Acetone Gas Sensing Properties

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。

Using the chemical co-precipitation,the doped Zn（OH）2 with Al mass fractions of0%,7%,9% and 11% were developed.And the doped Zn（OH）2with the fixed Al mass fraction of 9%and different Sn mass fractions were also prepared.The ZnO powder samples were obtained after annealing at 500,700 and 900 ℃.The gas sensors were prepared by coating on the Al2O3 ceramic tube surface with the dip coating method.The crystal structure and surface morphology of the sample were characterized by X-ray diffraction（XRD）and scanning electron microscope（SEM）.The gas sensing properties were detected by the gas sensor test system.The effects of Al-Sn co-doped amount on the gas sensing properties of ZnO thick films were studied,and the gas-sensing mechanism of Al-Sn co-doped ZnO thick films was discussed.The experiment results show that the doped ZnO thick film surface is loose porous structure and the Al-Sn codoped ZnO gas-sensing material has good selectivity to acetone.The sensitivity of the doped ZnO sample with Al mass fraction of 9% and Sn mass fraction of 3% reaches 12 792 at the operating temperature of 75 ℃,and the response and recovery time are 1 and 3 s,respectively.