【作者】 吴术习；

【导师】 周东祥；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2008， 硕士

【摘要】 本文通过丝网印刷技术和气溶胶辅助化学气相沉积技术研究了气敏膜的制备及膜的气敏特性。采用水热法分别制备纳米SnO2和In2O3粉体,通过加入微量In2O3掺杂,并调节玻璃粉加入量为5 wt%,以丝网印刷技术制备气敏厚膜,烧结温度调节为700℃。XRD、SEM测试表明厚膜表面的SnO2平均粒径为10 nm,厚膜表面为多孔结构。气敏测试结果表明:In2O3掺杂为7 wt%的厚膜元件有较好气敏性能,在40℃下能识别2 ppm的H2S气体,灵敏度为2.66;对30 ppm H2S灵敏度可达621。在热清洗后有较好的稳定性。通过水热掺杂法制备了In2O3和TiO2、活性Al2O3掺杂的厚膜气敏元件,分别可以识别300 ppm和800 ppm的甲烷气体。以SnCl2的乙醇溶液为前驱物,采用气溶胶化学气相沉积的方法研究了气敏薄膜的制备,系统研究了沉积时间、沉积温度、前驱物的浓度对薄膜电阻、气敏性能的影响。优化得出了制备纯SnO2的最佳工艺流程。XRD测试表明薄膜的主要成分为SnO2,无杂质。测试表明薄膜在25℃下对50 ppm H2S气体灵敏度可达97,无需热清洗电压变化值可以恢复90%以上。以Cu(CH3COO)2的乙醇溶液为前驱溶液利用气溶胶化学气相沉积方法实现了CuO掺杂改性。研究了掺杂方式、沉积时间、退火温度对薄膜气敏性能的影响。优化的掺杂工艺流程。SEM分析表明经过掺杂后的薄膜为多孔状薄膜,粒径为约为40 nm。经过掺杂后的薄膜在室温下对H2S气体的响应特性、恢复特性、稳定性都有很大改善。薄膜在25℃下对5 ppm和100 ppm的H2S气体灵敏度分别为3.7和928,室温下对100ppm H2S气体响应时间和恢复时间为100 s和130 s,无需加热清洗。最后,从缺陷化学的角度对薄膜的H2S气体的敏感机理进行了分析。更多还原

【Abstract】 In this paper, screen-printing technology and Aerosol-Assisted Chemical vapor deposition were used to fabricate gas sensor, the properties of the sensors were deeply researched.Nanometer SnO2 and In2O3 powder were prepared through hydrothermal method. SnO2 powder doped with microdosage nanometer In2O3 and Sb2O3 was prepared into paste, then, was fabfricated into thick film and annealed at 700℃。XRD、SEM were used to analyse the microstructure of the films, the result showed that the particle size of the SnO2 nanoparticles on the film was 10 nm, the surface of film was porous. Gas-sensing testing of the film indicated that sensors which doped with 7 wt% In2O3 obtained the best gas-sensing properties: the film could identify 2 ppm H2S at 40℃and the sensitivity was 2.66; To 30 ppm H2S, the sensitivity reached 621, the sensor responsed quickly and could recover well after thermal cleaning. In2O3 and TiO2, Al2O3 doped thick films also were fabricated through hydrothermal, the sensors could detect 300 ppm and 500 ppm CH4 gas.Alcohol solution of SnCl2 was used as precursor, thin films were prepared by AACVD. The effect of depositing time, depositing temperature, concentration of solution on the conductivity and gas-sensing properties of the film were studied. The optimizing preparation method was generalized. The thin films also obtained excellent gas-sensing properties: the sensitivity to 50 ppm H2S at 25℃reached 97, the voltage change could response 90% without thermal cleaning.Alcohol solution of Cu(CH3COO)2 was used as precursor, CuO doped thin films were fabricated through AACVD. The effect of doping mode, depositing time, annealing temperature on gas-sensing properties of the film were studied. The optimizing doping process was concluded. SEM analysis indicated that the thin films were multihole, the average grain size was about 40 nm. The recovering/response properties to H2S at room temperature of the CuO doped thin films showed great improvement. At 25℃,the sensitivity to 5 ppm and 100 ppm H2S were 3.7 and 928 individually. Without thermal cleaning, the response time and the recovery time to 100 ppm H2S gas were100 s and 130 s individually. At last, the gas-sensing mechanism to H2S gas of thin film prepared by AACVD was analyzed by non-stoichiometric chemistry.更多还原