SnO_2复合薄膜甲烷气敏传感器研究进展

甲烷是具有稳定四面体分子结构的碳氢化合物,其键能大、分解困难且活性低,是煤矿安全生产的主要障碍及一种温室气体。SnO2半导体薄膜制备工艺简单、成本低廉、性能稳定,是甲烷传感器研发的主流气敏材料。科技人员进行了很多相关研究以提高传感器的性能,如新气敏材料的研究、催化剂/添加剂的使用、气敏机理的探索、传感器结构改进及气敏膜的表面修饰改性等。本文从气敏膜制备与改性、传感器结构设计及气敏机理研究三个方面,综述了近年来SnO2复合薄膜甲烷传感器的研究进展,结果表明:①应开发复合型金属氧化物半导体及高分子气敏材料,以提高灵敏度、选择性与稳定性;②研发微型智能传感器是未来发展的主要方向,而自组装技术应可用于制备金属氧化物半导体薄膜气体传感器微纳阵列;③气敏机理应与实验测试、材料设计及器件制备进行对照研究。     

纳米ZnO气敏传感器研究进展

半导体金属氧化物气敏传感器被广泛应用于有毒性气体、可燃性气体等的检测.ZnO是一种重要的半导体气敏材料,特别是纳米ZnO,由于其粒子尺寸小,比表面积大,成为被广泛研究的气敏响应材料之一.简要介绍了纳米ZnO气敏传感器的气敏机理、主要特性,综述了通过新型纳米形貌、结构制备以及元素掺杂改性提升纳米ZnO气敏性能等方面的研究进展,并进一步指出了纳米ZnO气敏传感器研究中存在的问题和未来的研究方向.     

H2S气敏材料研究进展

本文综述了固体电解质、氧化物半导体（体材、厚膜、薄膜）型H2S气敏材料的研究进展及其应用．特别介绍了常温薄膜型H2S气敏材料的最新研究动态．     

TiO2-WO3复合薄膜型气敏传感器性质研究

二氧化钛和三氧化钨是具有重要功能的无机n型半导体材料，常用来制备气敏传感器。本文利用电子束蒸发制备了TiO2-WO3复合氧化畅薄膜，在500℃下退火2h。通过SEM和XRD观察了该薄膜的形貌特性并进行了气敏测试。实验表明，该薄膜对酒精、丙酮和二氧化硫气体具有较强的敏感性。本文还研究了温度、复合浓度和气体浓度对薄膜气体传感能力的影响。     

气敏半导体陶瓷材料的发展与应用

本文概述气敏半导体陶瓷材料的发展历史,论述和评介目前发展中的几种气敏理论,探讨气敏半导体陶瓷材料存在的问题和发展方向。此外,还探讨了气敏半导体陶瓷材料的应用,并给出评价气敏陶瓷元件性能的主要指标。     

铁氧化物薄膜气敏材料的制备及性能研究评述

本文综合介绍近年来在铁氧化物薄膜气敏材料制备方法、性能方面的研究新进展 ,探讨了各种方法的特点。提出了今后铁氧化物气敏传感器的研究及改进方向     

氧化锌气敏传感器性能的改善及在民航系统的应用

氧化锌是多功能N型半导体材料,具有优良的气敏性能,在气体传感器方面具有广泛的用途。氧化锌气敏材料及测试方法进一步优化后,传感器具有更高的灵敏度和更广泛的适用性。对纳米氧化锌传感器的气敏机理、改善气敏性能的主要方法以及传感器在民用航空方面的应用做了详细的综述。     

ITO气敏材料的制备和掺杂工艺的研究进展

主要介绍了ITO薄膜的制备工艺和掺杂优化工艺,例举了两种气敏机理的推论以及掺杂优化的机理。指出今后ITO气敏材料的气敏机理将成为研究重点,新形态ITO材料的研发将成为主要发展方向。     

氧化物半导体丙酮气敏传感器材料研究与应用

低浓度丙酮气体的检测在监测工业生产、食品质量、畜牧业和疾病等中有重要的作用.综述了近年来氧化物半导体丙酮气敏传感器材料的研究进展,并对传感器材料的形态、制备方法、敏感机理及存在的问题进行了分析,指出了发展方向.     

利用无机盐制备γ-Al2O3粉体与薄膜的工艺技术研究

发明了γ-A12O3基陶瓷气敏传感器材料体系,并正研究其薄膜型传感器件.本文以廉价的无机盐Al(NO3)3·9H2O为原料,通过溶胶-凝胶法制备了勃姆石(γ-A1OOH)溶胶,然后经干燥、煅烧制备了γ-Al2O3的粉体,并通过旋转涂覆工艺制备了γ-A12O3的薄膜,应用X射线衍射(XRD)、X射线光电子能谱(XPS)、原子力显微镜(AFM)等现代分析技术对粉体的物相和薄膜的组分及表面形貌进行了表征,对γ-A1OOH溶胶制备过程中的一些影响因素进行了探讨,得出了比较好的制备γ-Al2O3基陶瓷粉体和薄膜型气敏传感器的工艺技术条件.     

Flexible Transparent Electronic Gas Sensors

Flexible and transparent electronic gas sensors capable of real‐time, sensitive, and selective analysis at room‐temperature, have gained immense popularity in recent years for their potential to be integrated into various smart wearable electronics and display devices. Here, recent advances in flexible transparent sensors constructed from semiconducting oxides, carbon materials, conducting polymers, and their nanocomposites are presented. The sensing material selection, sensor device construction, and sensing mechanism of flexible transparent sensors are discussed in detail. The critical challenges and future development associated with flexible and transparent electronic gas sensors are presented. Smart wearable gas sensors are believed to have great potential in environmental monitoring and noninvasive health monitoring based on disease biomarkers in exhaled gas.     

Application of ZnO single-crystal wire grown by the thermal evaporation method as a chemical gas sensor for hydrogen sulfide

A zinc oxide single-crystal wire was synthesized for application as a gas-sensing material for hydrogen sulfide, and its gas-sensing properties were investigated in this study. The gas sensor consisted of a ZnO thin film as the buffer layer and a ZnO single-crystal wire. The ZnO thin film was deposited over a patterning silicon substrate with a gold electrode by the CFR method. The ZnO single-crystal wire was synthesized over the ZnO thin film using zinc and activated carbon as the precursor for the thermal evaporation method at 800 degrees C. The electrical properties of the gas sensors that were prepared for the growth of ZnO single-crystal wire varied with the amount of zinc contained in the precursor. The charged current on the gas sensors increased with the increasing amount of zinc in the precursor. It was concluded that the charged current on the gas sensors was related to ZnO single-crystal wire growth on the silicon substrate area between the two electrodes. The charged current on the gas sensor was enhanced when the ZnO single-crystal wire was exposed to a H2S stream. The experimental results obtained in this study confirmed that a ZnO single-crystal wire can be used as a gas sensor for H2S.     

Microsensor based on low temperature cofired ceramics and gas-sensitive thin film

A novel design of gas sensor using low temperature cofired ceramics (LTCC) and thin film technologies is presented. The LTCC structure is composed essentially of two ceramic layers with interlayer thick film Pt heater, interdigitated electrodes on top, contact pads and metallic connections realised by vias. The thin films of both SnO₂ and In₂O₃, intentionally doped and activated, were deposited on top of the structure. With some modifications of the lamination process and heat treatment parameters, the authors obtained the upper ceramic layer with the roughness not exceeding 250 nm, what was suitable for thin film technology. The films deposited onto such LTCC structure revealed the sensing properties very similar to the reference films deposited onto glass. The gas-sensitive films were tested with changing concentrations of reducing and oxidising gases in air. The necessary sensor working temperature was obtained and stabilised using a custom-built digital controller. The low heat capacity of the sensor structure enabled also a sinusoidal temperature control. The satisfactory results obtained by the authors indicate that the connection of LTCC and thin film technologies can lead to the fabrication of good quality gas sensors.     

Synthesis and integration of tin oxide nanowires into an electronic nose

Single crystal nanostructures of semiconducting tin oxides have been fabricated and characterized as sensing materials for implementation in an electronic nose. The nanowires exhibit exceptional crystalline quality and a very high length-to-width ratio, resulting in enhanced sensing capability as well as long-term material stability for prolonged operation. A sensing device based on SnO₂ nanowires has been fabricated and comparatively tested in an array of chemical sensor with conventional thin film sensing device. Preliminary measurements ethanol/water mixtures demonstrate that nanowire-based sensors can be favourably implemented in the electronic nose and that they perform comparably with the conventional thin film layers.     

Investigation on New Types of Semiconducting Ceramic Gas Sensors

A series of new types of semiconducting ceramic gas-sensing materials, Al₂O₃-based semiconducting ceramics, have been invented. Hydrogen and methane gas sensors have been made from these materials with different metal oxide additives. These gas sensors have various advantages, such as very good gas selectivity, nearly linear relationship between sensitivity and gas concentration, lower operating temperature, fast recovery time, and good anti-humidity property. The preparation and properties of these semiconducting ceramic gas sensors are presented in this paper.     

氢敏元件的种类及半导体薄膜材料在其中的应用

随着氢燃料电池技术在汽车应用中的日益完善,对高性能氢敏元件的需求也更加迫切。本文介绍了采用不同工作原理制备的氢敏元件的种类,着重描述了半导体薄膜材料的工作原理和改性途径,并针对我国目前研究较少的Ga2O3新型薄膜材料进行了较为详细的综合论述。     

Oxygen sensors: Materials, methods, designs and applications

Advancement of gas sensor technology over the past few decades has led to significant progress in pollution control and thereby, to environmental protection. An excellent example is the control of automobile exhaust emissions, made possible by the use of oxygen gas sensors. Since early 1970's there have been sustained studies on oxygen sensors and has led to development of sensors for various applications with varying performance characteristics. Solid electrolyte based potentiometric, amperometric and metal oxide based semiconducting resistive type sensors are used for high temperature applications. For solution-based pollution monitoring, dissolved oxygen sensors based on Clark electrodes have played a major role. More recently, for biological and medical applications, optical oxygen sensors are beginning to have an impact. In this review, we focus on both high temperature as well as dissolved oxygen sensors and compare the different methods of oxygen sensing, discuss underlying principles, and outline the designs and specific applications.     

聚吡咯/二氧化钛复合薄膜的制备及气敏性研究

运用静电力自组装和原位化学氧化聚合相结合的方法制备了聚吡咯/纳米二氧化钛(PPy/TiO₂)复合薄膜, 并进行了紫外－可见光谱分析和原子力显微镜分析. 采用平面叉指电极制备了PPy/TiO₂复合薄膜气体传感器, 研究了其在常温下对有毒气体NH₃和CO的敏感性. 最后测试了该传感器的温度湿度特性. 结果表明, 该传感器对NH₃具有较高的灵敏度, 对CO几乎没有响应. 同时讨论了复合薄膜沉积时间对气敏特性的影响, 实验表明当沉积时间为20min时, 该传感器的NH₃敏感特性最好.     

Chemical gas sensor application of open-pore mesoporous thin films based on integrated optical polarimetric interferometry

Chemical gas sensors that employ integrated optical polarimetric interferometry were fabricated by the sol-gel synthesis of transparent mesoporous thin films of TiO2-P2O5 nanocomposite on tapered layers of TiO2 sputtered on tin-diffused glass waveguides. Atomic force microscopy images of the mesoporous thin film clearly show the open pore mouths on the film surface that favor rapid diffusion and adsorption of gas-phase analytes within the entire film. Adsorption of gas and vapor induces changes (Deltan) in the refractive index of the mesoporous thin film that lead to shifts in the phase difference between the fundamental transverse electric and magnetic modes simultaneously excited in the glass waveguide via single-beam incidence. Upon exposure to NH3 gas at concentrations as low as 100 ppb in dry air at room temperature, the sensor exhibits a reversible change in the phase difference with the response and recovery times of less than 60 and 90 s, respectively. It is unexpected that the sensor is unresponsive to either NO2 or C6H6 vapor, leading to a somewhat selective sensitivity to NH3. Determination of Deltan was carried out with a combination of the experimental results and the theoretical calculations. The sensor design represents a novel, effective, and easily accessible approach to mesoporous thin-film-based integrated optical chemical sensors.     

Post treatment of plasma-polymerized SnOx organic-like films with poly ethylene glycol for improving CO gas sensitivity

In this study, a new room temperature type gas sensor device based on plasma deposition of tetramethyltin (TMT) and O2 organically hybridized film followed by post treatment on the deposited film was developed for improving CO gas sensitivity and distinguishing from methane, butane, and carbon monoxide gases in the test environment. Plasma deposited SnOx thin film was first produced from TMT and O2 gas mixtures at room temperature, and then post treatments on the SnOx thin films were carried out by either spin coating with poly ethylene glycol (PEG) or surface grafting with p-styrenesulfonic acid sodium salt (Nass). It was found that the gas sensor spin coating post treated with PEG exhibits linear response to CO gas with the sensitivity not affected by methane and butane gases. For CO concentrations ranging from 30 to 650 ppm, steep change in the sensor resistance can be detected without warming up the sensor.