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1.
本文报道了一种SnO2气敏传感器感机理的新模型。SnO2晶粒表面势垒由3个过程控制:(1)氧吸附(作电子受主)和脱附,(2)还原性气体附(作电子施主)和脱附,(3)表面氧化还原反应。据此可以很好地解释实验中发现的氧化压对气敏传感器响应的影响。  相似文献   

2.
合成了新型的有机半导体LB膜气敏材料(COTDMAPP),其LB多层膜拉制在场效应晶体管上,形成了具有LB-OSFET结构的化学场效应晶体管(ChernFET),该器件置于NO2,NH3,CO和H2S等有害气体中,结果表明在NO2气氛中元件漏电流IDS发生变化,并可检测到2ppm的NO2.这种器件的气敏特性在于FET的电流放大作用及LB膜的有序性的影响.  相似文献   

3.
SnO_2-Sb薄膜材料的制备及气敏性能   总被引:3,自引:0,他引:3  
利用等离子体化学气相沉积法制备了SnO2-Sb导电薄膜,测试了SnO2-Sb的气敏效应。结果表明,该薄膜对NO2气体有较好的气敏特性。当测试温度升高,其气敏响应时间相差无几,但恢复时间变短,同时气敏灵敏度相对提高,当温度达到200℃以上时,灵敏度基本恒定。同时还可看出,不同阻值的薄膜其气敏灵敏度相差不大。  相似文献   

4.
本文综述了集成气体传感器的发展过程的工作机理,讨论了Schottky气敏二极管、MOS气敏二极管、MOS气敏场效应厚膜集成气体传感器和集成气体传感器阵列。  相似文献   

5.
Fe2O3:SnO2薄膜的气敏透射光学特性   总被引:1,自引:0,他引:1  
梁振斌  郑顺镟 《激光杂志》1997,18(3):23-26,36
用溶胶--凝胶法制备Fe2O3:SnO2薄膜,研究了它的气敏透射光学特性,分析了实验结果,并解析了气敏光学透射机理。  相似文献   

6.
本文研究了用溶胶凝胶法制作二维SnO2;TiO2混合薄膜并测量了它在氨气氛中的气敏透射谱,发现对低浓度委组最佳灵敏区显示出对二维薄膜厚度的依从性。利用这些现象可制成对低浓度敏感且有气体选择性的气敏传感器件。  相似文献   

7.
气敏器件用SnO_2薄膜材料   总被引:2,自引:0,他引:2  
采用溶胶-凝胶法以SnCl2·H2O和ZrOCl2·8H2O为原料,制备出性能优良的纳米SnO2薄膜材料。用X射线衍射仪分析了晶相,TEM分析了微观结构。研究了掺杂、处理温度等对其性能的影响。在此基础上制作了SnO2薄膜气敏器件,并检测了其气敏特性。  相似文献   

8.
不同CO吸附类型对超细SnO_2气敏元件的作用   总被引:1,自引:0,他引:1  
本工作采用超细SnO2为基体,CO为检测气体,检测了烧结型SnO2元件在不同温度下的气敏效应.同时利用流动饱和法测试了粉体不同温度下对CO的可逆及不可逆吸附量.一方面通过新材料的使用,降低了元件的工作温度;另一方面,通过吸附测试与气敏效应的关联,认为:超细粉体低温时表面可逆CO量的存在,是其能够降低工作温度的主要原因.粉体表面的不可逆CO量直接影响着元件的响应输出(灵敏度).材料本身的吸附总量和气敏特性有着良好的对应关系.SnO2元件气敏效应的发挥是粉体表面可逆与不可逆吸附共同作用的结果.  相似文献   

9.
采用静电喷雾高温分解工艺制备SnO2气敏膜,并与Si3N4-SiO2集成多层介质膜,用催化金属Pt作栅电极,制成新型的MSIS结构气敏电容。通过检测平带电压的变化,研究对H2和O2的气敏特性,分析其气敏机理并提出了检测的物理模型.  相似文献   

10.
李杰  张兴娟 《电子科技》2001,(21):48-48
本文讨论一种可装于燃气灶或抽油烟机上的系列燃气泄漏报警器,利用该装置,燃气灶或抽油烟机一旦出现燃气泄漏,就会立即发生声光报警。1、原理简述 本装置所采用的气敏探头为半导体式气敏传感器,工作原理是随着探头附近可燃气体浓度上升,通电预热后的半导体构件对敏感气体的吸附作用,内部化学反应加快,气敏探头感应体电阻值呈指数率下降。具体参数指标在探头附近燃气浓度从几个ppm至几千个ppm之间变化时,传感器的阻值从20K ~120K之间变化,这种电阻的变化被信号转换电路将其转变成可以测量的电信号。具体做法是将传感…  相似文献   

11.
A dual-gas sensor system is developed for CO and CO2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing (TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode (without rotation) and dynamic mode (with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million (ppm) in volume and 2.6 ppm for CO and CO2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO2, respectively. The reported sensor has potential applications in various fields requiring CO and CO2 detection such as in the coal mine.  相似文献   

12.
A novel H2 gas sensor based on a SnO2 nanostructure was operated at room temperature (RT) (25°C). The SnO2 nanostructure was grown on Al2O3 substrates by a sol–gel spin coating method. The structural characteristics, surface morphology, and gas sensing properties of the SnO2 nanostructure were investigated. Thin film annealing at 500°C produced a high-quality SnO2 nanostructure with a crystallite size of 33.98 nm. A metal–semiconductor–metal gas sensor was fabricated using the SnO2 nanostructure and palladium metal. The gas sensor exhibited a sensitivity of 2570% to 1000 ppm H2 gas at RT. The sensing measurements for H2 gas at different temperatures (RT to 125°C) were repeatable?for 50 min. Sensor sensitivity was tested under different H2 concentrations (150 ppm, 250 ppm, 375 ppm, 500 ppm, and 1000 ppm) at different operating temperatures. Adding glycerin to the sol solution increased the porosity of the SnO2 nanostructure surface, which increased the adsorption/desorption of gas molecules which leads to the high sensitivity of the sensor. Therefore, this H2 gas sensor is a suitable?portable?RT gas sensor.  相似文献   

13.
A dinaphtho[3,4-d:3′,4′-d′]benzo[1,2-b:4,5-b′]dithiophene (Ph5T2)-modified copper phthalocyanine (CuPc) single crystal nanowire field-effect transistor (FET) with gas dielectric was fabricated as an organic gas sensor. This device exhibits the high response and the excellent controllable selectivity at room temperature. Its detection limit for NO2, NO, and H2S is down to sub-ppm level. Prior to surface modification, the CuPc nanowire FET shows the response as high as 1088% to 10 ppm H2S, but only 97.5% to 10 ppm NO2. After Ph5T2 modification, the response to 10 ppm H2S is decreased by one order of magnitude, but is dramatically improved up to 460% to 10 ppm NO2. The responses towards H2S and NO2 respectively for pristine and the modified sensor are higher than those of most reported organic sensors. The gas-sensing results reveal that Ph5T2 modification can transform the selectivity of the sensor from H2S to NO2. The controllable modulation of gas selectivity is related to the formed organic heterojunctions between CuPc and Ph5T2, where the hole carriers of CuPc nanowire are modulated by these heterojunctions, resulting in the changed adsorption behavior towards different gases.  相似文献   

14.
通过简单的水热法在金电极上刺备了氧化锌纳米棒,从而制成了气体传感器。研究了氧化锌纳米棒的结构和特性,发现用该材料制成的气体传感器时于500ppm的NH3和H2在150℃下有较灵敏的反应,并探讨了产生传感效应的机理。该传感器制备方法简单、廉价、环保,适合大批量生产,有望应用于工业生产和日常生活的气体探测。  相似文献   

15.
Antimony triselenide (Sb2Se3) nanoflake-based nitrogen dioxide (NO2) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb2Se3 nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO2 gas concentrations from 0.1 to 100 ppm. These Sb2Se3 nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb2Se3 nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO2 gas flow of only 1 ppm. As a result, the Sb2Se3 nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations.  相似文献   

16.
A capacitive gas sensor using tin oxide (SnO2) nanoparticles has been integrated with a microstrip patch antenna for detecting ethylene gas emanated from climacteric fruits. The decrease in sensor capacitance owing to the presence of ethylene (0-100 ppm) changes the antenna resonant frequency and return loss (by 7 MHz and 9.5 dB) which can be monitored wirelessly.  相似文献   

17.
In this paper, the authors propose a new and simple Nafion-based NO2 amperometric sensor, a dedicated measurement system, and a measurement protocol. The system has a linear response to NO2 concentration, and a sensitivity up to 90 nA/ppm. Moreover, the developed sensor shows a satisfactory repeatability and a low cross-sensitivity to common interfering gases such as CO and oxygen.  相似文献   

18.
We demonstrate the chemiresistive NO2 gas sensor based on DBSA doped PPy–WO3 hybrid nanocomposites operating at room temperature. The sensor was fabricated on glass substrate using simple and cost effective drop casting method. The gas sensing performance of sensor was studied for various toxic/flammable analytes like NO2, C2H5OH, CH3OH, H2S and NH3. The sensor shows higher selectivity towards NO2 gas with 72% response at 100 ppm. Also the sensor can successfully detect low concentration of NO2 gas upto 5 ppm with reasonable response of 12%. Structural, morphological and compositional analyses evidenced the successful formation of DBSA doped PPy–WO3 hybrid nanocomposite with uniform dispersion of DBSA into PPy–WO3 hybrid nanocomposite and enhance the gas sensing behavior. We demonstrated that DBSA doped PPy–WO3 hybrid nanocomposite sensor films shows excellent reproducibility, high stability, moderate response and recovery time for NO2 gas in the concentration range of 5–100 ppm. A gas sensing mechanism based on the formation of random nano p–n junctions distributed over the surface of the sensor film has been proposed. In addition modulation of depletion width takes place in sensor on interaction with the target NO2 gas has been depicted on the basis of schematic energy band diagram. Impedance spectroscopy was employed to study bulk, grain boundary resistance and capacitance before and after exposure of NO2 gas. The structural and intermolecular interaction within the hybrid nanocomposites were explored by Raman and X-ray photoelectron spectroscopy (XPS), while field emission scanning electron microscopy (FESEM) was used to characterize surface morphology. The present method can be extended to fabricate other organic dopent-conducting polymer–metal oxide hybrid nanocomposite materials and could find better application in the gas sensing.  相似文献   

19.
In this paper, quartz crystal microbalance (QCM) gas sensors coated with polyehtyleneimine (PEI) was utilized for carbon dioxide (CO2) detection. The sensing mechanism is based on the availability of reversible acid-base reactions between CO2 molecules and PEI at room temperature. The experimental results revealed that the PEI/starch sensor exhibited much higher sensitivity than that of pure PEI, and showed approximate linearity over a concentration region ranging from 500 ppm to 8000 ppm. The influence of humidity had also been investigated. Furthermore, the response and recovery time deceased as the operation temperatures increased. Finally, sensitivity loss after conservation for several days and reversibility of the sensors had been discussed.  相似文献   

20.
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