掺杂对ZnO气敏性能的影响研究

ZnO是最早发现的金属氧化物气敏材料,对其掺杂一直是研究的一个热点.采用机械球磨法制备了22种不同掺杂的纳米ZnO气敏材料,通过乙醇、丙酮、苯的测试,系统对比了掺杂元素的化学性质,如离子半径、化合价、元素周期等对ZnO气敏性能的影响.掺杂元素的离子半径为0.072～0.088 nm时,传感器对被测气体的响应比掺杂其他离子半径的高.不同周期掺杂元素对ZnO纳米气体传感器的选择性有一定的影响.     

金属氧化物掺杂对TiO2气敏特性的影响

掺杂金属氧化物可显著提高TiO2的气敏这一特性，正逐渐成为研究的热点。本文综述了掺杂金属氧化物对TiO2气敏特性的主要影响及机理；总结了目前研究中所掺杂的十多种金属氧化物，并就各种掺杂物对TiO2气敏特性的作用进行了具体分析。     

CeO2掺杂对ZnO薄膜气敏特性的影响

ZnO薄膜进行CeO2掺杂,研究掺杂含量和热氧化对薄膜结构、表面、晶粒尺寸及气敏特性的影响.结果显示,用热蒸发制备的高纯Zn膜经500℃热氧化,获得c轴取向ZnO多晶薄膜.掺CeO2可抑制晶粒生长使颗粒细化平均粒径减小,同时改善了ZnO薄膜的体相化学计量比,Zn与O的比例从未掺杂时1∶1.28降到1∶1.191.XPS...     

金属氧化物半导体气敏材料的研究进展

金属氧化物是重要的半导体材料,具有较好的气敏特性,作为气敏材料被广泛应用。本文较系统地对金属氧化物气敏材料的研究现状作了阐述,重点介绍了复合氧化物气敏材料的研究状况,并对其气敏性质进行了概述。展望了金属氧化物半导体气敏材料今后的研究重点及发展方向。     

金属氧化物半导体气敏传感器研究进展

金属氧化物半导体气敏传感器由于具有低成本、低功耗、高灵敏度、快速响应、稳定耐用等特点而引起人们广泛关注。本文主要介绍了金属氧化物半导体气敏传感器的基本原理、分类、器件结构、气敏机制,重点介绍了金属氧化物气敏传感器性能提升方法。通过掺杂改性、改变微观尺寸和形貌以及形成各种复合结构等都有利于金属氧化物传感器气敏性能的增强,并对其增强机理进行了一定的解释。     

金属氧化物半导体SO2气体传感器的研究现状

介绍了气敏机理,总结了近年来国内外基于金属氧化物半导体的SO2气敏材料的研究现状,指出了基于金属氧化物半导体SO2气体传感器的不足之处,提出设计复合材料、优化合成方法是提高SO2气敏材料敏感特性的研究方向.     

Pd掺杂ZnO纳米线的乙醇气敏特性研究

研究以贵金属Pd作为掺杂剂的ZnO纳米线敏感元件的乙醇气敏性能。采用水热法在叉指电极上直接制备出具有c轴取向的ZnO多晶纳米线。用SEM,XRD和EDS分析手段观测了材料的微观结构,并对其乙醇气敏性能进行了测试。实验结果表明:对于体积分数为200×10-6的乙醇气体,Pd掺杂的ZnO纳米线在灵敏度(8.17)、工作温度(325℃)和响应恢复时间(15,8s)上优于纯的ZnO纳米线。最后,对Pd掺杂的气敏机理进行了讨论。     

半导体金属氧化物气敏材料敏感机理概述

本文结合半导体金属氧化物的电学特性，从气体分子与半导体金属氧化物气敏材料相互作用的角度出发，对其气敏机理作一概述。由于半导体金属氧化物气敏机理与氧存在密切相关，因而从表面吸附、催化氧化反应的角度研究气敏机理对研究反应机理、提高气敏性能、开发新型气敏材料和掺杂剂有着重要的意义。     

气敏薄膜表面吸附结合能的宏观测量方法

在采用溅射方法制备的ZnO、SnO2/CeO2纳米平面气敏薄膜实验基础上,总结了气敏薄膜响应时间和恢复时间τc的宏观测量的特征时间次方规律.显微物理化学特性对研究气敏薄膜是十分必要却难以由微观直接测量获得,我们通过上述实验结果与气敏表面反应和表面吸附理论相结合,间接测量了气敏表面吸附结合能Ea这一微观特性,从而表明可以用宏观测量方法研究气敏薄膜的一些微观特性.     

过渡金属氧化物掺杂氧化铁气敏性能的研究

<正> 金属氧化物气敏材料,目前主要有SnO_2系、ZnO系、Fe_2O_3系商品化的三大类。其中氧化铁系气敏材料价格低廉,粘着力好,不需要贵金属催化剂等优点,八十年代开始大量研究。但是由于α-Fe_2O_3灵敏度较低,而γ-     

掺杂对CdSnO_3气敏性能的影响

研究了贵金属及金属氧化物对CdSnO_3气敏性能的影响.发现不同的Fe_2O_3、La_2O_3的掺入量对材料的气敏性能有不同的影响,贵金属Pt、Pd、Ag及某些金属氧化物对CdSnO_3的灵敏度和选择性也有影响.掺入La_2O_3及MgO的CdSnO_3可作酒敏材料,掺Pd的CdSnO_3可作乙炔敏材料.     

Parallel-packaged multiple-gas microsensors based on hollowed nanostructures of doped tin oxides

Microsystem Technologies - Hollow nanofiber multiple-gas microsensors containing a ceramic package in parallel were developed via doping metal oxides in tin oxide (SnO2) and electrospinning and...     

The oxide cathode revisited

Abstract— A new theory is presented on the emission degradation or slump of oxide cathodes at current drawing and on the beneficial effect of doping the emitting layer with rare‐earth oxides. It was shown that during its lifetime, a gradual voltage difference is built up in the oxide layer, which eventually leads to the decomposition of BaO and O₂ during current drawing. This causes an emission slump in life‐tested cathodes. Doping with rare‐earth oxides prevents this build up due to the electron donating capability of these materials.     

低阻TiO_2基三甲胺气体传感器性能分析

按旁热式结构采用以TiO2为基质对InSb2O3Nb2O5氧化物不同的重量比去掺杂研制成的三甲胺(TMA)气体传感器,大幅度降低了加热功率和其在空气中的阻值,器件对响应TMA气体具有灵敏度高、响应时间快、恢复时间短、长期稳定等特点,对干扰气体NH3具有良好的选择性。     

低功耗In_2O_3基LPG气敏元件

采用In2O3超细粉体,掺杂Au和金属氧化物(SiO2,Fe2O3等),按照直热式气敏元件工艺制成珠状气敏元件,通过Al2O3 Pd的表面催化层处理,研制出功耗低于100mW(在空气中)的液化石油气(LPG)气敏元件。并分析了元件的气敏机理。     

Explanation of the low oxygen sensitivity of thin film phthalocyanine gas sensors

The conductivity of phthalocyanine (Pc) is affected upon exposure to an atmosphere containing oxidizing molecules like oxygen, ozone, nitrogen oxides or chlorine. This phenomenon finds application in the use of thin phthalocyanine films as resistive gas sensors. Such sensors have shown that the sensitivity to oxygen is orders of magnitudes lower than that for the other oxidizing species. We explain this fact by quantifying the oxygen uptake and doping density of copper-, zinc-, manganese- and free base phthalocyanine films. The oxygen inside the film is found in molecular form as O₂. Only the metal phthalocyanines acquire significant doping levels upon exposure to oxygen. The number of charge carriers is four orders of magnitude lower than the uptake of molecular oxygen in the material. It explains the observation that resistive phthalocyanine gas sensors have low sensitivity for the detection of oxygen.     

Passivation of ZnO TFTs

Abstract— The impact of passivation processes on ZnO thin‐film transistors is reported. In general, passivation processes result in back‐channel doping, which corresponds to shifts in threshold voltage and changes in subthreshold slope. It was determined that ALD‐based passivation results in considerably smaller undesirable shifts than those observed with plasma‐based processes. Two approaches, one a bulk doping with ammonia and the other a surface treatment with hydrogen peroxide, to further mitigate the detrimental effects of the passivation process are described. After proper passivation, ZnO devices show negligible hysteresis, have excellent stability to bias stress, and maintain or improve the good transport properties of as‐deposited devices. Although the existence of grain boundaries has been assumed to be a point of concern for device stability in polycrystalline metal oxides, no evidence was found to suggest that the grain boundaries present in these ZnO thin‐film transistors have affected the device stability.     

Impact of high-thermal budget anneals on polysilicon as amicromechanical material

With the goal of facilitating the development of surface micromachined polysilicon MEMS with postprocessed on-chip circuitry, we have evaluated the Impart of a 1200°C 16-h anneal upon chemical-vapor-deposited (CVD) polysilicon under a variety of processing conditions. The results show that undoped polysilicon has a final stress of +10-20 MPa even when the films are vastly different as deposited and that phosphorus doping introduces a compressive trend that is evident only after the long anneal. X-ray diffraction, transmission-electron-microscopy (TEM), and atomic-force-microscopy (AFM) studies of the polysilicon are used to analyze the grain orientations, grain sizes, and surface roughness of the material. The effect of the long anneal on residual stress in wet thermal and CVD oxides is also presented. Overall, the results indicate that the thermal budgets of conservative circuit processes can be accommodated within the fabrication sequence of surface-micromachined polysilicon microstructures     

A highly sensitive and fast-responding sensor based on electrospun In2O3 nanofibers

In₂O₃ nanofibers with diameters of around 60 nm have been fabricated by electrospinning with a solution containing both poly (vinyl pyrrolidone) (PVP) and indium nitrate, followed by calcination in air at 700 °C. Without further adding catalysts or doping other metal oxides, the sensor based on the as-prepared indium oxide (In₂O₃) nanofibers showed high response and selectivity, fast response and recovery time towards ethanol gas. The simple preparation and excellent properties significantly advance the viability of electrospun gas sensors.     

ZnO nanowires for LED and field‐emission displays

Abstract— The use of ZnO nanostructures in various display applications is reported. Single‐crystalline vertically oriented nanowires with typical diameters of 100 nm and a length of 1–2 μm were grown at deposition temperatures below 100°C. Homogeneous growth over areas up to 50 cm² on Si as well as on various metallic, transparent, and flexible substrates were obtained. Visible electroluminescence in the region between 400 and 900 nm and narrow‐line near‐ultraviolet (UV) electroluminescence is demonstrated. The physical conditions leading to single‐crystalline growth at low temperature, the role of defects, and the possibility of doping are discussed. These issues present the main challenges on the road towards high emission rates in LED operation. Under certain conditions, sharply tipped wires can be grown that hold promise for field‐emission applications.