一种基于电子隧穿机制的柔性氢气传感器

氢气传感器在涉氢安全领域扮演着重要角色,随着可穿戴设备大量应用,柔性氢气传感器的发展日益受到重视。纳米粒子薄膜以其离散的纳米颗粒状结构和独特的电学响应性质成为了理想的柔性氢气敏感材料。通过在聚对苯二甲酸乙二醇酯(PET)柔性衬底上沉积钯(Pd)纳米粒子薄膜构筑了一种柔性氢气传感器。通过上百次反复弯折,该传感器体现了较好的机械性能和电学稳定性,气敏性能在弯折循环前后无衰减。通过系统研究应变状态下的氢气响应性质,发现拉应变使Pd纳米粒子薄膜的氢气响应度增大,而压应变效应则相反。其原因主要归结为应变导致的纳米颗粒间距变化,拉应变产生的较大的纳米颗粒间距会使得传感器电流基线降低,且足够大的纳米粒子间距更能容纳Pd纳米粒子吸氢导致的晶格膨胀,反之亦然。此外,拉应变使Pd纳米粒子薄膜对氢气的响应时间显著缩短,而压应变产生的效果则相反。该氢气传感器探测范围达到0~10%,响应时间可达数秒量级,探测下限为25×10^-6。在低氢气浓度范围内,响应度ΔI/I0与P1/2H2呈现线性关系,对4%浓度氢气的响应度可达600%,灵敏度可达3.28% Pa-1/2。这些结果表明,该传感器具备优异的传感性能,在柔性气体传感器领域具有极大应用潜力。     

金(Au)/钯(Pd)复合膜表面等离子共振氢敏传感器基因优化

提出了一种新颖的基于波长调制的Au/Pd复合膜SPR氢敏传感器结构,采用遗传基因算法对Au/Pd复合膜氢敏传感器的灵敏度进行了数值计算和优化,优化结果表明:Au(2 nm)/Pd(27 nm)结构的复合膜氢敏传感器可获得最佳的灵敏度,与通常使用的单一纯Pd(20 nm)膜氢敏传感器相比,不仅氢敏传感器的敏感膜的稳定性得到改善,而且灵敏度也提高了近3倍.     

氧化锌气体传感器的制备及甲烷检测特性研究

甲烷(CH4)是电力变压器油纸绝缘中溶解的主要故障特征气体,能有效反映运行变压器油纸绝缘故障.气体传感检测是油中气体在线监测、分析的关键.基于水热法,制备了氧化锌(ZnO)纳米片和纳米球气敏材料及传感元件,基于实验室搭建的微量气体检测平台测试了其对CH4的检测特性.研究表明:基于ZnO纳米片制作的气体传感器比纳米球传感器对CH4表现出更好的气敏性能,对50μL/L CH4的最佳工作温度降低了约60℃,同时对低浓度(1μL/L～20μL/L)CH4表现出较高的线性度和长期稳定性.本研究对研制高性能的ZnO基CH4气体传感器奠定了基础.     

含Pd纳米线SAW气体传感器氢敏特性分析

基于COMSOL Muhiphysics软件,建立了含Pd纳米线的声表面波(SAW)传感器三维模型,以YZ铌酸锂为压电基底,叉指电极固定于基底表面,分析了Pd纳米线长度对模型本征频率的影响.对电极施加20V电压得到了不同氢气体积分数下电极上电导纳值和本征频率偏移值.通过磁控溅射制作了Pd薄膜,设计了SAW传感器测试夹具,得到了传感器氢敏特性.将仿真值与实验值进行对比,得到了含Pd纳米线氢敏材料的SAW传感器具有比含面形Pd膜传感器更高的灵敏度.     

磁致伸缩非晶合金双层结构传感器研究进展

介绍了磁性非晶合金材料及其在传感器中的应用现状。通过分析基于磁致伸缩非晶合金的双层结构及其制作工艺与传感原理,重点介绍了接触型和非接触型传感结构在加速度、位移、位置、曲率和温度传感方面的应用成果和最新进展,讨论了目前研究中存在的一些问题和未来磁性非晶合金和磁致伸缩非晶合金双层结构传感器的发展趋势。     

基于非晶合金的位移/位置传感技术新进展

非晶合金是一种具有长程无序、短程有序微观结构的新型软磁材料,以其独特性能在传感领域具有很大的应用潜力。按照磁致伸缩的强度不同,详细介绍高磁致伸缩和近零磁致伸缩非晶合金位移/位置传感器,重点对传感机理进行分析和比较,指出该传感技术发展的特点和趋势。     

MOFs基纳米酶的生物传感应用研究

MOFs基纳米酶因其自身具有较高的原子利用率、独特的几何和电子结构，在催化反应中表现出更高的催化活性，目前已经成为纳米酶研究的热点。在该文中，总结了MOFs基纳米酶的分类及其在生物传感领域的应用进展，并对比了基于不同MOFs基纳米酶传感器的构建及其检测性能，阐明了MOFs基纳米酶应用的前景和面临的挑战，旨在为MOFs基纳米酶的发展提供参考。     

光纤法布里珀罗氢气检测技术

实现对密闭容器内的微量氢气进行快速准确的测量,对提高产品的贮存安全性有重要意义,为此开展了一种具有实用性的新型光纤传感器研究.介绍了基于溅射钯银合金膜的非本征法布里-珀罗光纤氢气传感器系统的工作原理.通过应力传递过程的分析,建立了法布里-珀罗腔腔长变化与氢浓度关系的数学模型,并推导出传感器灵敏度计算方法.实验通过在一定浓度下研究该传感器的氢响应特性,证实了该氢气检测方法的可行性,并且其理论模型与实验结果吻合较好.     

钯栅厚度对气敏MOS晶体管灵敏度的影响

本文介绍了一种Pd栅MOS结构的半导体气敏器件。在叙述Pd栅MOS晶体管气敏机理的基础上,着重讨论了钯栅厚度对器件灵敏度的影响。实验结果证明,Pd栅MOS晶体管的灵敏度随着钯栅厚度的增加而降低。在工作温度不太高的条件下,灵敏度随钯栅厚度的变化基本上不受温度的影响。另外,文中还扼要地阐述了钯栅M0S晶体管的结构、制造技术及器件灵敏度的测试原理和方法。研究结果对于MOS结构的半导体气敏传感器的研制具有重要的意义。     

基于钯纳米颗粒导电沟道的室温型氢气传感器的研究

随着氢能的广泛应用,检测氢气(H₂)泄漏十分必要。采用溶剂热法合成钯(Pd)纳米颗粒,结合旋涂法从极大程度上简化了覆盖敏感层工艺,在利用微机电系统(MEMS)工艺制备的硅基金(Au)叉指电极上研究了基于“氢致Pd晶格膨胀效应(HILE)”的裂结式H₂传感器的敏感特性,为低成本批量化制备室温型氢气传感器提供了可行性研究。结果表明该传感器对H₂的响应值与Pd纳米颗粒在基底上的覆盖率密切相关：覆盖率在一定范围内越大,响应值越小。在室温下,该类传感器对500×10^-6～2 500×10^-6H₂表现出了较快的响应速度：响应时间在5 s左右,恢复时间在25 s左右,具有较高的响应值：在2 500×10^-6H₂气氛下高达83%,有较好的选择性和稳定性。     

Pd/PVDF thin film hydrogen sensor system based on photopyroelectric purely-thermal-wave interference

A novel sensitive solid-state sensor system for trace hydrogen gas detection has been developed as a next generation device to earlier photopyroelectric (PPE) hydrogen sensors. The basic principle of the sensor is based on the technique of PPE purely-thermal-wave interferometry recently developed in this Laboratory. The active element of the sensor is a thin polyvinylidene fluoride (PVDF) pyroelectric film, sputter-coated with Pd on one surface and with a Ni–Al alloy electrode on the other surface. Unlike the conventional PPE hydrogen sensors, this new sensor produces a coherent differential PPE signal in a single detector, rather than using two detectors (one active, the other reference) and complicated electronics. The measurement results show that the signal noise level, the detectivity and the signal dynamic range are improved by more than one order of magnitude compared with the conventional single-beam method. The operating characteristics have been examined for three different thicknesses of Pd coating on the same thickness PVDF-film detector. The signal generating mechanism, attributed to the change of the optical absorptance of the Pd coating when exposed to hydrogen, and/or the shift in the Pd work function, is also discussed.     

Experimental and modeling studies of acetylene detection in hydrogen/acetylene mixtures on PdM bimetallic metal-insulator-semiconductor devices

The effect of the composition of the metal gate on acetylene response in hydrogen/acetylene mixtures was tested for a number of metal-insulator-semiconductor (MIS) devices with bimetallic gates. The motivation for this study was that bimetallic catalysts are employed in the commercial acetylene hydrogenation process because of superior performance compared to the pure metals. A variety of metal compositions and operating temperatures were tested, with the largest reproducible acetylene response observed for a 15% Ag/Pd sensor at 398 K. Kinetic modeling of the relevant surface reactions on Pd and bimetallic PdAg provided insights into how temperature, feed concentration, and Ag content affected response. The model predicted that significant coverages of carbon species formed on the surface, mainly CH(s) and C(s) on Pd and CCH(s) on PdAg, and that these species strongly influenced sensor responses. The dynamic changes in the surface coverages of carbonaceous intermediates after acetylene introduction were correlated with a response overshoot seen experimentally. The model indicated that the superior performance of Ag/Pd sensors relative to Pd sensors could be explained in terms of a higher hydrogen consumption rate. These results indicate a strong connection between the high reaction rates observed for industrial Ag/Pd acetylene hydrogenation catalysts and acetylene response in Ag/Pd MIS sensors.     

High temperature field effect hydrogen and hydrocarbon gas sensors based on SiC MOS devices

The growing need for reliable, efficient, high temperature hydrogen and hydrocarbon monitoring has fueled research into novel structures for gas sensing. Metal oxide semiconductor (MOS) devices employing a catalytic metal layer have emerged as one of the leading sensing platforms for such applications, owing to their high sensitivity and inherent capability for signal amplification. The limited operating temperature of such devices employing silicon as the semiconductor has led research efforts to focus on replacing them with devices based on silicon carbide (SiC). More recently, MOS devices having different oxide layers exhibiting improved sensing performance have emerged. Considering the amount of research that has been carried out in this area in recent times, it is important to elucidate the new findings and the gas interaction mechanisms that have been ascribed to such devices, and bring together several theories proposed by different research groups. In this paper we first highlight the needs which have driven research into SiC based field effect hydrogen and hydrocarbon sensors, illustrate the various structures being investigated, and describe the device evolution and current status. We provide several sensing examples of devices that make use of different oxide layers and demonstrate how their electrical properties change in the presence of the gases, as well as presenting the hydrogen gas interaction mechanisms of these sensors.     

Metal (Pd, Pt)-decorated carbon nanotubes for CO and NO sensing

Using the first-principles calculations, we investigated adsorption of CO and NO gas molecules on the Pd- and Pt-decorated single-walled carbon nanotube (SWNT). The metal-decorated SWNTs exhibit strong affinity toward the gas molecules. Our results reveal that the CO and NO gas molecules can be chemisorbed on the Pd or Pt atom, accompanying with the large binding energy and significant charge transfer. Adsorption of these gases would affect the electronic conductance of the materials, which can serve as a signal of gas sensor. In particular, adsorption of NO generates the magnetic properties to the metal-decorated SWNT, which can also serve as a sensitive signal for chemical sensors. After adsorption of CO and NO, the changes in binding energy, charge transfer and conductance may lead to the different response in the metal-doped CNT-based sensors. It is expected that these results could provide helpful information for the design and fabrication of the CO and NO sensing devices.     

导波光学氢敏传感器研究进展􀀂

为了了解光学氢敏传感器研究与现状,我们介绍了导波光学氢敏传感器的主要应用场合和氢敏感膜的结构与镀膜工艺,对有代表性的光纤微透镜型、表面等离子共振光纤型、光纤倏逝波场型、光纤光栅和集成波导型氢敏传感器的结构及性能做了详细的分析,并对导波光学氢敏传感器的未来发展做了展望.     

Modeling of radiation sensitivity of hydrogen sensors based on MISFET

The paper presents the electrophysical and electrical models of hydrogen and radiation sensitivities of the integrated sensors with MISFET sensing elements based on the structure Pd–Ta₂O₅–SiO₂–Si. The models take into account the influence of electrical circuits and modes, chip temperatures, surface-state density and radiation parameters on the hydrogen sensitivity of the sensors.     

SiC气体传感器

SiC肖特基二极管气体传感器可以广泛应用于检测气体排放物和气体泄露。通过采用PdCr合金 ,可以提高Pd/SiC气体传感器的灵敏度。同时 ,在Pd层和SiC之间引入SnO2 作为界面层也是提高其灵敏度的一种有效途径。进一步的研究表明 ,SnO2 层的大小也对传感器的性能有着重要影响。     

LPG sensing properties of Pd-sensitized vertically aligned ZnO nanorods

One-dimensional (1-D) vertically aligned ZnO nanorods are synthesized on glass substrate through a simple chemical route and their liquefied petroleum gas (LPG) sensing properties are studied. The morphology and structure of vertically aligned ZnO nanorods has been characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The LPG sensing properties of the vertically aligned ZnO nanorods are improved significantly after palladium (Pd) sensitization. The unsensitized vertically aligned ZnO nanorods exhibited the maximum response of 37% at 573 K upon exposure to 2600 ppm LPG, which improved to 60% at operating temperature of 498 K after the Pd sensitization. The Pd-sensitized vertically aligned ZnO nanorods showed more selectivity towards LPG as compared to CO₂. Our results demonstrate that the chemically grown vertically aligned ZnO nanorods along with Pd sensitization are promising material for the fabrication of cost effective and high performance gas sensors.