共查询到18条相似文献,搜索用时 257 毫秒
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讨论一种对二氧化氮具有高灵敏性的WO3纳米薄膜的制备方法.当基片温度为室温,溅射混合气体(O2/Ar)的比例为1:1时,用直流反应磁控溅射法制备的薄膜,经过两步热处理(300℃/600℃),得到纳米结构WO3气敏元件.通过XRD、XPS和SEM对该薄膜的晶体结构和化学成分进行分析,用静态配气法测试NO2气敏特性.在Si3N4基片上制备的这种薄膜对空气中较低浓度的NO2(体积分数为0.1×10-5~3×10-5)具有优异的敏感特性和响应特性,最佳工作温度为150℃,在此温度下对其他一些气体(如CO,C2H5OH,NH3)的敏感性很差,显示出良好的选择性. 相似文献
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以CuCl2·H2O为主要原料,抗坏血酸作还原剂,聚乙二醇-20000(PEG-20000)作表面活性剂,利用化学混合法制备了纳米晶结构的Cu2O纳米立方体。研究了pH值对Cu2O纳米结构的影响,并用XRD和SEM对产物的物相和形貌进行了表征。将粉体制成气敏元件,气敏性能测试结果表明:该Cu20纳米晶对乙醇气体具有较高的灵敏度和选择性。600℃热处理2h材料气敏特性最好,在最佳工作温度(360℃)下对体积分数为0.006%的乙醇气体灵敏度可达到38%,达到了口腔乙醇气体体积分数检测限度0.008%的要求。 相似文献
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SnO2薄膜的电学气敏特性与光学气敏特性研究 总被引:1,自引:1,他引:0
用射频磁控反应溅射法制备了SnO2薄膜,并分别测量薄膜在乙醇气体中的电学气敏特性和光学气敏特性。对实验结果的分析表明,SnO2薄膜对乙醇气体有较强的电学气敏效应和光学气敏效应。利用SnO2薄膜的电学气敏特性适合检测较低浓度乙醇气体,而利用SnO2薄膜的光学气敏特性能检测较高浓度乙醇气体。 相似文献
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针对多孔硅气敏传感器在室温下对NO2气体灵敏度较低、选择性不强的问题,采用双槽电化学腐蚀法制备多孔硅,然后在多孔硅顶部溅射沉积金属钨薄膜并经高温热处理氧化形成WO3纳米线,制备出WO3纳米线修饰多孔硅结构及其气敏传感器,对WO3纳米线/多孔硅材料进行了SEM和XRD分析,测试了传感器室温下对NO2的气敏特性。结果表明,制备WO3纳米线的最佳热处理条件是700℃,此温度下增加金属钨膜溅射时间可提升WO3纳米线的生长密度? 所制备的传感器对NO2气体表现出反型气敏响应,特别是溅射1min金属钨的样品显示出优异的NO2室温探测能力与选择性,对4×10-6NO的气敏灵敏度是单纯多孔硅样品的 5.8倍。 相似文献
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采用非醇盐溶胶—凝胶工艺在A l2O3基片上旋转涂敷制得掺Ag的SnO2薄膜。原子力显微镜和扫描电子显微镜分析显示:薄膜晶粒呈球形,600℃热处理粒径为20 nm左右。热处理温度升高,晶粒尺寸增大。气敏性能采用静态法测试,掺Ag薄膜对体积分数为50×10-6乙醇和汽油气体的灵敏度分别为32.7和4.9,与未掺Ag薄膜的14.4和7.2相比较,提高了乙醇气体灵敏度,抑制了汽油气体灵敏度,使选择性得到改善。直流加热条件下,试样电阻和电容在老化初期变化较大,数天后趋于稳定,复阻抗分析表明:长期稳定性与晶粒间界处电阻和电容值的变化有关,来源于晶界势垒高度和势垒宽度的变化,其本质可能是直流偏压作用下晶界层中的离子迁移。 相似文献
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用真空蒸发的方法,在1.33×10-3Pa的真空中,蒸发SnO2,ZnO获得超微粒结构的SnO2-ZnO复合膜。当复合膜中ZnO质量分数为20%时,SnO2-ZnO复合膜对乙醇气体的灵敏度为40,膜的方电阻值也较低,为0.01×103Ω/□。复合膜经热处理后,其电学性能也得到改善,当温度t=600℃时,ZnO质量分数为20%的SnO2-ZnO复合膜热处理后,其膜对乙醇气体有较高的选择性,灵敏度为60。当t=400℃时,对掺有Sb2O5质量分数为450×10-6,ZnO质量分数为20%的SnO2-ZnO复合膜进行热处理,其方电阻仅为0.003×103Ω/□,具有优良的导电性能。 相似文献
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《Sensors and actuators. A, Physical》2006,125(2):405-410
In situ patterned zinc oxide (ZnO) thin films were prepared by precipitation of Zn(NO3)2/urea aqueous solution and by microcontact printing of self-assembled monolayers (SAMs) on Al/SiO2/Si substrates. The visible precipitation of Zn(OH)2 from the urea containing Zn(NO3)2 solution was enhanced by increasing the reaction temperature and the amount of urea. The optimized condition for the ZnO thin films was found to be the Zn(NO3)2/urea ratio of 1/8, the precipitation temperature of 80 °C, the precipitation time of 1 h and the annealing temperature of 600 °C, respectively. SAMs are formed by exposing Al/SiO2/Si to solutions comprising of hydrophobic octadecylphosphonic acid (OPA) in tetrahydrofuran and hydrophilic 2-carboxylethylphosphonic acid (CPA) in ethanol. The ZnO thin film was then patterned with the heat treatment of Zn(OH)2 precipitated on the surface of hydrophilic CPA. The ZnO gas sensor was exposed to different concentrations of C3H8 (5000 ppm), CO (250 ppm) and NO (1000 ppm) at elevated temperatures to evaluate the gas sensitivity of ZnO sensors. The optimum operating temperatures of C3H8, CO and NO gases showing the highest gas sensitivity were determined to be 350, 400 and 200 °C, respectively. 相似文献
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《Sensors and actuators. B, Chemical》2000,62(2):102-108
In order to apply WO3 thin films to the NOx gas sensor, WO3 thin films (3000 Å) were fabricated by using dc reactive sputtering method on alumina substrate and assembled as a unit of an NOx gas sensor by adopting a patterned heater on the back side of substrate. The deposition temperatures of WO3 thin film were changed from 200°C to 500°C, and then post-annealed for the crystallization for 4 h at 600°C. There were no WO3 phases at the substrate temperature of 200°C, but the crystalline phases of WO3 thin film were appeared with the increase of substrate temperature from 200°C to 500°C. The post-annealing of as-deposited WO3 thin films at 600°C resulted in the enhancements of crystallinity, but it was observed that the quality of the final phases severely depends on the initial formation of phase during deposition. From the SEM images, crack free morphologies were found, which was different from the room temperature growth films. The sensitivity (Rgas/Rair) of as-deposited thin films was ranged from 4 to 10 for the 5 ppm NO test gas at the measuring temperature of 200°C. However, after post-annealing process at the temperature of 600°C, the sensitivities were increased around the values of 70–180 at the same test condition. These results show the WO3 thin films need to be processed at least at the temperature of 600°C for the well-improved sensitivity against NOx gas. It was also observed that the recovery rate of a sensing signal after measuring sensitivity was faster in the in-situ sputtered films than in the evaporated films or room temperature sputtered films. 相似文献
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Wan-Young Chung
Chang-Hyun Shim
Duk-Dong LeeSoon-Don Choi
《Sensors and actuators. B, Chemical》1994,20(2-3):139-143A silicon-based SnO2 gas sensor has been fabricated for monitoring liquified petroleum gas (LPG), commonly used as town gas. The gas sensor is made by silicon IC technology together with SnOf2 thin-film processing. The whole chip with a size of 9 mm x 9 mm consists of nine sensors (three by three array). each sensor is supported by a thin membrane of SiO2/Si3N4/SiO2 layers that provides a low thermal mass and prevents heat conduction through the surrounding substrate material. Tin oxide thin film is prepared by thermal evaporation of metallic tin granules and subsequent thermal oxidation of the metallic film at 600 °C. To form the SnO2(Pt) thin film, a layer of Pt with a thickness of several tens of angstroms is sputtered onto the tin oxide film and heat treated at 500 °C in air for several hours in order to stabilize its electrical response. The fabricated SnO2(Pt) microsensors exhibit about 85 and 92% sensitivities to 5000 ppm C3H8 and 5000 ppm C4H10 (the main components of LPG) at 250 °C, respectively, and show a rapid response time of less than 5 s. 相似文献