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采用溶胶-凝胶法,制得Al_2O_3掺杂质量分数分别为0、2.96%、4.96%、6.96%的纳米Al_2O_3-ZnO粉体,样品经700℃退火后对其物相及表面形貌进行表征,测试了不同Al_2O_3掺杂量Al_2O_3-ZnO样品的气敏特性,研究了结晶粒径、掺杂浓度、工作温度等对元件气敏特性的影响;通过对元件进行控温控湿老化实验,研究了老化温度、相对湿度对元件稳定性的影响;并根据气体吸附、脱附模型与半导体能带理论,对气敏机理进行了进一步的讨论。结果表明:Al_2O_3-ZnO对丙酮表现出良好的选择性和稳定性,掺杂为4.96%Al_2O_3的Al_2O_3-ZnO,经700℃退火后,在64℃下,对含量为100×10~(-6)(体积分数)的丙酮的灵敏度为29.24,响应时间和恢复时间均为2 s;丙酮含量低至10×10~(-6)时,灵敏度为3.23,响应时间和恢复时间分别为4 s和7 s。
The nano-Al 2 O 3 -ZnO 2 powders with Al 2 O 3 doping content of 0, 2.96%, 4.96% and 6.96% were prepared by sol-gel method. The phase and surface morphology of the samples were characterized by annealing at 700 ℃ , The gas sensing properties of Al_2O_3-ZnO samples with different amounts of Al_2O_3 doping were tested. The influence of crystal grain size, doping concentration and operating temperature on the gas sensing properties of the devices was studied. Through the temperature-controlled humidity aging test, The effects of aging temperature and relative humidity on the stability of the device were also discussed. The gas sensing mechanism was further discussed according to the theory of gas adsorption, desorption and semiconductor banding. The results showed that Al 2 O 3 -ZnO showed good selectivity and stability to acetone. The Al 2 O 3 -ZnO doped with 4.96% Al 2 O 3 was annealed at 700 ℃ and the content was 100 × 10 -6 ) (Volume fraction) of acetone was 29.24, response time and recovery time were 2 s; acetone content as low as 10 × 10 -6, the sensitivity was 3.23, the response time and recovery time were 4 s and 7 s.