WO_3气敏薄膜的膜厚对气体响应时间的影响

用简单的模型分析了薄膜气体传感器敏感材料的膜厚对气体响应时间的影响,该模型适用于分析WO3薄膜气体传感器的敏感特性。薄膜气体传感器的敏感特性依赖于气体原子在薄膜内的扩散和与气敏材料的响应;而气体原子在薄膜内的扩散是由薄膜厚度决定的。经过推导得出理论上WO3薄膜对NH3的敏感特性,并将其与实验所得的数据进行比较。最后,给出了WO3薄膜气体传感器的气敏特性与气体在其膜内扩散和膜厚的关系。     

Cr2O3-Al2O3甲烷敏感材料的研究

采用室温固相合成法制备了不同含量的Cr2O3-Al2O3系列敏感材料,试验研究了Cr2O3催化剂含量和焙烧温度对甲烷气体催化活性的影响,并考察了甲烷传感器灵敏度大小和敏感材料的长期稳定性。结果表明：该法制备的Cr2O3-Al2O3系列敏感材料具有较好的低温催化活性,且随Cr2O3含量的增加,催化剂的低温活性增强。综合考虑敏感材料的催化活性、灵敏度和稳定性,400℃焙烧制备的Cr2O3含量为30％的Cr2O3-Al2O3敏感材料对甲烷低温催化燃烧有较好的催化性能。     

基于声表面波技术探测微量气体的理论分析

声表面波延迟线振荡器的频率对沉积在延迟线表面上的薄膜很敏感,在延迟线路径上覆盖一层具有选择性的吸附薄膜,这层薄膜吸附对其敏感的气体物质后,其质量密度、弹性参数、介电常数、电导率都将发生变化。给出了传感器的理论分析,根据检测需要,设计最优化的气体传感器。     

传感器薄膜结构的改进与响应时间的分析

提出了一种具有立体敏感效应的新型气体传感器敏感薄膜结构模型,即将传统的厚度均匀的平面型传感器敏感薄膜改进为由多条半圆柱凸起与多条沟槽相间隔的立体敏感结构。并根据扩散反应理论对新型和传统型2种薄膜结构的传感器响应时间进行了分析与比较,证明新型敏感结构的传感器具有更短的响应时间;分析了半囱柱凸起间距的相对系数对传感器响应时间的影响,得出了最佳取值。     

声表面波气体传感器的理论分析

声表面被气体传感器的敏感物质是在声表面波传播途径上覆盖一层具有选择性的吸附薄膜，这些薄膜在吸附对其敏感的气体物质后，质量密度，弹性参数。介电常数，导电率都将发生变化，通过理论分析，导出了该传感器的测量方程．     

一种新型三维敏感气体传感器的研究

在平面微电极式结构的基础上,提出了一种新型薄膜气体传感器,其主要结构引用了离散阵列的概念,将传统的长方体型薄膜改进为由多条小长方体有间隔的并行排列的离散结构,使敏感薄膜具有了三维敏感效应。根据半导体气敏薄膜的扩散响应理论,对传感器的响应时间和灵敏度特性进行了理论分析,证明新型传感器具有响应时间更短、灵敏度更高的优点;并分析了薄膜厚度对传感器响应时间的影响。     

基于PVDF的高压电性薄膜制备工艺研究

针对国内的聚偏二氟乙烯(PVDF)压电传感器仅限于实验室阶段,仍需要大量进口的现状,通过对PVDF压电特性分析,结合传感器产品的结构,进行PVDF压电传感器的制备工艺的研究。对工艺过程中的初始薄膜制备、单轴拉伸、高压极化和磁控溅射等主要工艺进行制备工艺参数的探索,获得了PVDF压电敏感薄膜,并采用聚酰亚胺材料进行封装,得到PVDF压电传感器。对该传感器进行关键参数静态压电系数d_(33)的测试,结果为13.1PC/N,获得了满足实际工程使用的PVDF压电传感器产品。     

PVDF压电薄膜制作传感器的理论研究

用PVDF压电薄膜设计传感器是近年来在传感器领域研究的一个新热点,通过对PVDF压电薄膜的压电性能的分析,根据弹性力学的薄板理论和压电效应的物态方程,导出PVDF压电薄膜的传感方程,并对偏转角口的情况进行了讨论;为用PVDF压电薄膜制作传感器提供理论基础。     

基于MEMS的镍薄膜加热器催化传感器研究

设计了基于微机电系统(MEMS)工艺,以镍薄膜作为加热体的新型催化传感器。通过磁控溅射沉积、刻蚀等工艺制成镍薄膜加热器,并对其进行了稳定化热处理以及防氧化聚合物涂层处理。传感器性能测试结果表明:镍薄膜加热器具有良好的抗高温氧化能力;气氛老化可缩短50%的老化时间;甲烷气体浓度与灵敏度呈良好的线性关系;对甲烷的灵敏度约为30 m V/1%Vol;传感器功耗约为150 m W,零点和灵敏度年漂移小于1. 5%LEL。     

MWCNT-WO3薄膜双声路SAW NO2气体传感器

以金属钨粉,H2O2,CH3OH和多壁碳纳米管(MWCNT)为原料,在双声路声表面波(SAW)器件的测量声路上制作了MWCNT-WO3薄膜,提出并实现了一种MWCNT-WO3薄膜双声路SAW NO2气体传感器。由于MWCNT和WO3对NO2气体都有敏感作用,而且碳纳米管的毛细作用、以及MWCNT的加入都增加了气体的接触面积,提高了NO2气体的吸附和敏感作用。同时,SAW器件的双声路结构消除了由于外界测量条件改变引起的测量误差,也进一步提高了传感器的可靠性和准确性。实验结果表明,该传感器对各种浓度的NO2气体具有好的响应特性,在31.2×10-9到20×10-6范围内,传感器的响应灵敏度为9.8kHz/1×10-6,比单一MWCNT或WO3薄膜对NO2气体具有更好的灵敏度和线性特性。     

掺钯二氧化锡气敏薄膜的实验研究

XPS分析表明,用直流溅射法制备的掺钯薄膜气敏元件,钯的溅射率比锡高,在薄膜中钯的含量高于靶中的含量、和纯SnO_2薄膜相比,此元件对还原性气体有很高的灵敏度,尤其对H_2和CH_4.对于该元件的气敏机理也作了初步探讨.     

ZnO压电薄膜声传感器的有限元分析

阐述了ZnO压电薄膜声传感器的结构和工作原理,并用ANSYS 9.0对压电薄膜声传感器进行了静态分析、模态分析和谐响应分析。通过静态分析,得到压电薄膜声传感器的灵敏度为16.4 mV/Pa;模态分析得出了传感器的第一阶固有频率为12.379 kHz;谐响应分析则获得感应电压与动态外力频率之间的关系。这些分析为此类声传感器的设计提供了理论依据。     

Thin-film electro-acoustic sensors based on AlN and its alloys: possibilities and limitations

Sputter deposited aluminum nitride (AlN) thin films have played a central role for the successful development of the thin film electro-acoustic technology. The development has been primarily driven by one device—the thin film bulk acoustic resonator, with its primary use for high frequency filter applications for the telecom industry. Recently, increased piezoelectric properties in AlN through the alloying with scandium nitride have been identified both experimentally and theoretically. This opens up new possibilities for the thin film electro-acoustic technology. Here expectations and discussions are presented on acoustic FBAR sensor performance when based on AlN as well as on such AlN alloys to identify possible benefits and limitations. Inhere, the distinction is made between direct and in-direct (acoustic) use of the piezoelectric effect for sensor applications. These two approaches are described and compared in view of their advantages and possibilities. Especially, the indirect (or acoustic) use is identified as interesting for its versatility and good exploitation of the thin film technology to obtain highly sensitive sensor transducers. It is pointed out that the indirect approach can well be obtained internally in the piezoelectric material structure. Original calculations are presented to support the discussion.     

PdO纳米材料制备及室温甲醛气敏特性研究

采用水热合成的方法,以氯化钯(PdCl2)为原料,十二烷基三甲基溴化铵(CTAB)为分散剂,制备得到了四方结构的PdO材料,并利用X-射线衍射(XRD)、电子扫描显微镜(SEM)对得到的PdO颗粒进行了表征与分析.将制得的PdO材料制成传感器,在静态配气系统中测得了PdO材料对挥发性有机化合物(VOC)气体甲醛的敏感特性.结果表明,该PdO材料能够在室温(25℃)下对甲醛有很好的响应特性,对10×10-6甲醛响应达到3.90,测试浓度为0.1×10-6时,响应可达到1.84.     

Integration of displacement sensor into bulk PZT thick film actuator for MEMS deformable mirror

Bulk PZT thick film actuator integrated with displacement sensor, the so-called self-sensing actuator, is presented in this paper. The PZT film is used as not only an actuating layer but also a displacement sensor, which is achieved by dividing the electrode on the top surface of the PZT film into two parts: central top electrode for actuating and outer annular sensor electrode for piezoelectric displacement detection. When the actuator moves, the piezoelectric charge is induced in the outer annular PZT due to the piezoelectric effect. The total amount of accumulated charge is proportional to the stress acting on the PZT, which is in turn proportional to the actuator displacement. By collecting the piezoelectric charge, the actuator displacement can be detected. A theoretical model is proposed to determine the structure parameters of the sensor and predict the sensor sensitivity. Experiments were performed on the micro-fabricated sensor integrated PZT thick film actuator, and the measured piezoelectric charge is close to the theoretical predictions. The integrated piezoelectric sensor has a displacement sensitivity of approximately 4 pC/nm. In addition, the integration of displacement sensor into the actuator needs no additional fabrication process and has no influence on the actuator performances.     

A piezoelectric micro-cantilever bio-sensor using the mass-micro-balancing technique with self-excitation

A biosensor was developed for using in a Lab-On-a-Chip (LOC). The sensor detects the change in the resonance frequency of a micro-cantilever with a piezoelectric film. This is the mass micro-balancing technique, which has been successfully used for detecting bio-materials in the quartz crystal microbalance (QCM). The PZT film, a piezoelectric film, is designed to act as both sensor and actuator. The geometry of the micro cantilever is optimized to maximize the sensitivity and minimize the environmental effects such as viscous damping and added mass effect in liquid. The fabricated sensor is composed of a 100 μm long, 30 μm wide, and 5 μm thick cantilever with a 2.5 μm thick piezoelectric (PZT) layer on it. The ratio of thickness to length of the micro cantilever is very high compared to others in micro cantilever-based studies. This high aspect ratio is the key to maximize the sensitivity and minimize the environmental effects. The fabricated micro sensor was tested by detecting the mussel gluing protein, the insulin-anti insulin binding protein and the poly T-sequence DNA.     

一种采用穴番-A敏感膜的新型声表面波瓦斯传感器的研究

本文利用笼形超分子材料穴番-A对甲烷分子的特异性包合作用,提出了一种能够在室温下工作的采用穴番-A敏感膜的新型声表面波瓦斯传感器。设计研制了中心频率为300 MHz的低损耗、高Q值SAW谐振器,并以所研制的谐振器构成双通道差分振荡器。分别以点涂法和旋涂法在传感通道SAW谐振器表面进行了敏感膜的镀膜。通过实验观察对比了采用两种镀膜方式的SAW瓦斯传感器在常温下对5%甲烷气体的响应。实验结果显示点涂镀膜的传感器响应约为1 kHz,远大于旋涂镀膜方式。AFM表面形貌表征显示了敏感膜表面粗糙度是造成这一差异的主要原因。实验还研究了传感器对不同浓度甲烷气体的响应,结果表明传感器响应随气体浓度降低而减小,两者存在良好的线性关系,测试灵敏度为205 Hz/%,检测下限约为0.2%。     

Tin oxide microsensor for LPG monitoring

A 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 SnO_f2 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.     

Preparation of BST ferroelectric thin film by metal organic decomposition for infrared sensor

Barium strontium titanate (Ba_1−xSr_xTiO₃) ferroelectric thin films have been prepared by metal organic decomposition (MOD) on Pt/Ti/SiO₂/Si and on micromachined wafer with an aim to fabricate dielectric bolometer type infrared (IR) sensor. The XRD pattern and D–V hysteresis curve of the film have been measured in order to investigate the effects of the final annealing temperature and annealing time on the property of the film. The results show that the films annealed at 700 °C or 800 °C all have good perovskite structure, while the film annealed at 800 °C has better ferroelectric loops. Films annealed at 800 °C with different annealing time from 5 to 60 min show a similar perovskite structure, among which films annealed at 30 and 60 min condition have the better ferroelectric loops. Temperature coefficient of dielectric constant (TCD) of the MOD made BST thin film on micromachined substrate is about 1%/K. The uniformity of the BST film on micromachined Si wafer also has been confirmed to be good enough for operation of sensor array. Chopperless operation has been attained and infrared response evaluation of the fabricated sensor also has been carried out with R_v of 0.4 kV/W and D^* of 1.0×10⁸ cm Hz^1/2/W, respectively.     

基于环形微热板的ZnO微气体传感器设计

提出一种新型的设有环形结构微热板的硅基ZnO微气体传感器。利用ANSYS软件,将环形电极结构与传统的蛇形结构进行温度分布的模拟仿真,发现该结构能供给传感器更高的温度且中心温度分布均匀,进而解决了现有传感器功耗大的缺点。通过对RF磁控溅射ZnO薄膜的工艺摸索,得出了适宜作气敏薄膜的制备参数。该传感器在250℃下对（200-1000）×10-6CH4气体有很好的响应。