【作者】 徐甲强；

【导师】 沈嘉年；

【作者基本信息】 上海大学 ， 材料学， 2005， 博士

【摘要】 经过四十多年的研究发展,传感器工作者已基本解决了金属氧化物半导体气体传感器的灵敏度和选择性问题,使之在可燃气体、有毒有害气体的检测和控制方面取得了广泛地应用。但目前市售的半导体气敏元件还存在选择性偏低、稳定性差的缺点,严重限制了这一具有巨大市场价值的产品的推广应用。本文选择发现最早、应用广泛的氧化锌气敏材料和功耗低、选择性好的氧化铟气敏材料为研究对象,从材料结构控制和气敏机理研究两方面入手,系统地研究了氧化物气敏材料的制备、结构、组成与气敏性能的关系,取得了较好的研究结果。具体如下:1.用水热法、溶剂热法合成了结构均匀、分散性好的氧化锌纳米棒、纳米线等一维纳米材料和氧化锌晶须、亚微米棒,用XRD、ED、SEM、TEM、XPS等对这些材料的结构、组成和形貌进行了表征。通过考察添加剂、反应温度、时间等因素对合成材料结构及形貌的影响,给出了氧化锌纳米棒、纳米线和晶须的生长机理。2.采用化学沉淀法、微乳液法、超声辐射溶胶-凝胶法、水热法、溶剂热法制备了形状均匀、分散性好的球形、方块形、针形和棒形氧化铟,用XRD、ED、SEM、TEM、XPS、TG-DSC等表征了合成氧化铟的结构、组成和形貌;采用溶剂热法一步合成了立方氧化铟纳米晶;通过考察表面活性剂、助表面活性剂、反应原料及配比等对氧化铟结构和形貌的影响,得知油酸存在是微乳-溶剂热法制备亚稳态六方氧化铟纳米棒的关键因素。3.通过静态配气法测试了不同结构氧化锌的气敏性能。与零维纳米颗粒相比,氧化锌纳米棒具有较高的气体灵敏度,氧化锌纳米线则具有较好的气敏稳定性;通过贵金属元素掺杂可显著提高氧化锌一维纳米材料的灵敏度并改善其选择性,使之有可能应用于酒精、硫化氢、液化气、乙醛、苯等气体的检测。4.与氧化锌气敏材料相比,氧化铟具有更低的功耗或工作温度;稀土掺杂可明显改善氧化铟对酒精和汽油的气体选择性,提高氧化铟对甲醛的灵敏度;根据氧化铟的电阻-温度曲线、灵敏度-温度曲线、颗粒尺寸对氧化铟灵敏度的影响等结果推断氧化铟的气敏机理为表面吸附氧控制型,化学吸附氧的存在对氧化铟在空气中的阻值和检测气氛中的气体灵敏度起着关键的作用。5.通过气敏元件表面分析和比表面测试分析了氧化锌一维纳米材料灵敏度高于零更多还原

【Abstract】 Since gas sensors based on metal oxide semiconductor had been studied in 1962, researchers have basically resolved the problems of low sensitivity and poor selectivity of gas sensors. Recently, gas sensors have been widely used to detect or control inflammable and toxic gases. However, the commercial gas sensors have some disadvantages to overcome, such as the sensitivity non-high enough and shortage stability which caused a big limit in more spread application of the gas sensors provided with great marketable values. It is well known that zinc oxide is the earliest discovered and widely used gas sensing materials, indium oxide is the most valuable materials employed as gas sensor because of its low power consumption and relative high gas selectivity to toxic gas. Thus, we selected ZnO and In2O3 as our research objects, and systemically studied the synthesis of the materials with nanostructure, the relations of material structure, morphology component and gas sensing properties. Some progresses in improving stability and gas selectivity were gained with a view to the control of crystal shape and particle size as well as investigated results of gas sensing mechanism. The details of our research works are presented as follows:1 ZnO one-dimensional nanomaterials included nanorods and nanowires, whiskers and sub-microrods with single crystal structure, satisfactory morphology and high dispersity were synthesized by means of hydrothermal and solvothermal methods. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and electron diffraction (ED). The effects of the factors such as additives, reactive temperature, reactive time on the structure and morphology of the samples were studied. The crystal growth mechanisms of ZnO nanorods, nanowires and whiskers were also suggested.2 The global, cubic, needle and rods-shaped indium oxide nanomaterials were made by chemical precipitation, micro-emulsion, ultrasonic-assisted sol-gel, hydrothermal and solvothermal processes, respectively. The crystal structures, morphology and composition of the samples are characterized by XRD, ED,SEM, TEM,HRTEM, XPS and TG-DSC. In2O3 nanocrystal can be synthesized one-step without any heating更多还原