【作者】 赵士超；

【导师】 季振国；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2006， 博士

【摘要】 纳米氧化锌颗粒是重要的氧化物半导体材料,具有广泛的应用范围。本文提出了一种新的制备纳米氧化锌的方法和工艺,对其结构、光、电性能进行了表征,并对纳米氧化锌的应用进行了初步研究。 我们知道,目前纳米氧化锌颗粒的制备方法很多,但现有各种制备方法通常存在工艺复杂、成本高、粒径与均匀性难以控制、产品纯度低的缺点,很难达到光、电应用所需的要求。因此很有必要研究一种纯度高、粒度可控且均匀性好、生产成本低、可规模化生产的纳米氧化锌颗粒的制备方法。为此,本文发明了一种利用金属锌与双氧水氧化反应生成氢氧化锌溶胶,再通过喷雾热解以及热处理生成粒径可控的纳米氧化锌颗粒的方法。该方法工艺简单、成本低,可以实现规模化生产,特别需要指出的是该方法不同于一般的湿化学方法,因为无需添加沉淀剂因而产品纯度很高。 本文比较系统地对制备的纳米氧化锌进行了表征。利用XRD分析了影响氧化锌颗粒粒径的因素,包括金属锌与双氧水反应时的反应温度、反应时间、反应物浓度、溶液PH以及产物的热处理温度。实验结果发现,热处理温度对粒径的影响最大,热处理温度从200℃升高到600℃时,纳米氧化锌颗粒的粒径从5nm增大到25nm,因此在本论文发明的方法中,纳米颗粒粒径可以通过控制热处理温度来控制。通过FTIR和Raman光谱研究了纳米氧化锌颗粒的中原子的键合形态,实验发现E₁声子频率随着粒径减小出现较大的蓝移,而E₂声子频率只有在粒径较小时才出现较明显的红移,分析表明氧化锌纳米颗粒内部可能存在应力。利用AFM、SEM和SAXS对氧化锌的形貌进行了表征,AFM和SEM照片显示氧化锌形貌为球形颗粒,SAXS分析结果显示这些颗粒没有明锐的相界面,其质量分形维数为1.9。 纳米氧化锌由于其优异的光电性能和潜在的应用价值因而成为研究热点之一。本文在成功获得纯度高、粒径可控的纳米氧化锌颗粒的基础之上,进一步研究了纳米氧化锌颗粒的光、电、气敏性质。本文利用紫外可见吸收谱和荧光光谱分别研究了纳米氧化锌颗粒的紫外可见光吸收性能和光致发光性能。经过分析发现,纳米氧化锌颗粒的光学禁带宽度一方面由于量子约束效更多还原

【Abstract】 ZnO nanoparticle is an important oxide semiconductor material, which is of potential applications in many areas. In this paper, we invented a novel method to prepare ZnO nanoparticles. The crystalline structure, optical and electrical properties of the nanoparticles were characterized, and some of the applications were investigated.Untill now, various techniques have been employed to prepare ZnO nanoparticles, however these methods are usually complex and costly in order to control the particle size, the size uniformity, and the purity, which are very important for optical and electrical device applications. So, it is necessary to find a new method to synthesize ZnO nanoparticles with the following properties: high purity, size controllability, size uniformity, low cost and mass production. In this paper, a novel method for fabricating ZnO nanoparticles was described: Firstly, zinc （Zn） was oxidized in hydrogen peroxide （H₂O₂） solution to form Zn（0H）2 sol;secondly, the sol was sprayed and annealed to form ZnO nanoparticles. Since no precipitation reagent was added, the purity of ZnO nanoparticles prepared by this method is super to that of ZnO nanoparticles prepared by other liquid chemical method.The as prepared ZnO nanoparticles were characterized systematically. The particle size was investigated by X-ray diffraction （XRD）. The influence parameters on the particle size, including: oxidation reaction temperature, reaction time, H₂O₂ concentration, solution PH value and processing temperature were investigated by XRD. It is found that the processing temperature has great influence on the particle size. The particle size of ZnO nanoparticles is in the range of 5-25 nm for annealing temperature from 200 ℃ to 600 ℃. By controlling the annealing temperature , the particle size can be easily controlled. The atomic bonding characters oin the nano-particles were investigated by FTIR and Raman spectrum, The El mode frequency shows blue-shift, while the E2 mode frequency shows red-shift as the particle size decreases. These resultsshow that there exists the stress in the nano-crystalline ZnO.particles.The microstructure of ZnO nanoparticles was investigated by AFM, SEM and SAXS. Both AFM and SEM results show that nano-ZnO was spheric shaped, and the results of SAXS show that the particles have no sharp interface and the fractal dimensionality is 1.9.The research has been focusing on nano ZnO due to its excellent optical and electrical properties and its prospects in optoelectricals applications. On the basis of the successful preparation of nano ZnO particles with high purity and size controllability, the optical properties, the electrical properties, and gas sensitivity of ZnO nanoparticles were characterized. The optical properties of ZnO nanoparticles were studied by UV-vis absorption and photoluminescence （PL）. The optical energy bandgap show typical blue-shift as the partcile size decreases, which is attributed to the quantum effect, but the ultraviolet PL peaks show red shift compared with the optical energy bandgap of the bulk ZnO, which is attributed to the acceptor-exciton complex.At last, we investigated the applications of ZnO nanoparticles. Firstly, we prepared nano-ZnO embed SiO2 glass. The photoluminescence of the nano ZnO embed S1O2 glass and the influence parameters were investigated. Secondly, the mesoporous S1O2 glass was obtained by treating the nano ZnO embedded SiO2 glass in HC1 solution. Thirdly, conductive Al-doped ZnO nanoparticles were prepared, and the measurement of the resistivity of nano-ZnO was discussed. Then, ZnO nanoparticle film based photodetector and photoconductance were investigated. The results show that the nanoparticles with larger particle size has high responsivity. Finally, ZnO nanoparticle films made gas sensor was demonstarted, which can work at room temperature without a heater.更多还原