【作者】 白伟；

【导师】 朱自强；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 在本论文中，我们分别采用了热蒸发法、溶液处理法以及水热合成法等不同方法，制备出形貌各异的ZnO微米／纳米结构，如纳米梳、纳米棒、纳米线、纳米带、针管状纳米结构、双节棍纳米结构、毛笔状纳米结构、由纳米棒组成的纳米花状结构、纳米盘和由纳米盘组成的纳米花状结构。对所得到的部分样品的生长机制做了一定的探讨，并且定性地分析了部分样品的光致发光性质和场发射性质。本论文的主要内容和创新点有以下几个方面。一、在实验的早期，用传统的热蒸发法制备出ZnO纳米梳和纳米棒。适当改变温度条件后，我们得到了杂乱的纳米线和形貌稍异的纳米梳等纳米结构。用扫描电子显微镜（SEM）表征所制备的样品的形貌和结构。对纳米梳的晶体特性用选区电子衍射（SAED）和透射电子显微镜（TEM）进行表征而用X射线电子衍射（XRD）表征其晶体结构。根据实验结果，定性地探讨了“阶梯状”纳米梳的生长机制，第一步：ZnO成核并沿着[01-10]晶向生长，形成侧面是±（0001）两个晶面，上下底面是±（2（?）0）晶面的纳米带结构；第二步：同时地，纳米棒的齿沿着晶向[0001]以较慢的速度生长，这可能与钎锌矿族的晶体结构特征有关。二、通过硫尿溶液刻蚀用热蒸发制备的纳米梳和纳米棒，我们得到了超薄的ZnO纳米带和尖头直径约为30nm的针管状纳米机构。用能量散射X射线探测器（EDX）鉴定是否有其它元素（如硫元素）掺入所得的纳米带和针管状结构中。定性地解释了超薄纳米带和针管状纳米结构的形成。最后，经溶液浸泡的样品和未经浸泡的样品的光谱和场发射等特性进行对比，结果显示硫尿中的氢离子不仅对形貌的形成有决定作用，而且在改善光谱和场发射性质方面同样有着重要的作用。三、利用六水硝酸锌（Zn（NO₃）₂·6H₂O）和六亚甲基四胺(C₆H₁₂N₄)，通过低温水浴合成了不同形貌的氧化锌微米／纳米结构（如花状结构、毛笔状结构、饼状结构和双节棍等）。对所合成的样品的形貌、晶体特性进行一定的测试和表征。对于不同的实验条件，如溶液浓度、衬底以及“温度变化”等进行了实验，并对实验结果做了定性地讨论。根据实验结果，我们给出了由棒状结构到毛笔状结构最后导致双节棍的形成机理。测试和分析了花状和毛笔状纳米结构的光学性质。四、我们采用化学纯的氯化锌（ZnCl₂）和氨水（NH₃．H₂O）两种化学试剂通过低温水浴合成了大面积的由纳米盘组成的ZnO微米／纳米花状结构。这种合成氧化锌微米、纳米结构的方法具有方法简单、成本低、条件温和以及对环境无污染等优点；另外与其他的化学合成方法相比较，本方法只采用了两种化学试剂，没有添加任何活性剂或者有机物，所以合成的微米／纳米材料纯度较高。这些氧化锌花状结构是由片状六边行组成，由于其具有大的比表面积，在化学传感器、光催化以及光存储等方面有着巨大的应用前景。对于不同的实验条件，如溶液浓度、生长时间、pH值和衬底等因素进行了实验，并对实验结果与生成条件之间的关系做了定性地讨论和分析，为大面积、低成本合成氧化锌微米／纳米结构提供一条实验途径。我们对部分样品做了室温光谱测试和分析，阐释了样品蓝绿光发射的机理。更多还原

【Abstract】 In this paper, ZnO micro/nanostructures with various morphologies, such as stepped nanocombs, nanorods, nanowires, nanobelts, nanorods with ～30nm pinheads, nanonunchakus, brush pen-like nanostructures, nanoflowers made up of nanorods, nanodisks and nanoflowers composed of nanoplates and so on, have been synthesized using different methods, including thermal evaporation, treatment through chemical solution and hydrothermal. Growth mechanisms of some samples were discussed, such as nanocombs, nanobelts, nanorods with ～30nm pinheads and nanonunchakus. We analyzed and discussed the photoluminescence and field emission properties of some products. Main works and innovations in this paper are as follows:1. Stepped ZnO nanocombs and nanorods were fabricated by the conventional thermal evaporation in the early experiments. Meanwhile, unorderly nanowires, nanocombs with different morphologies were obtained by changing the growth temperature. The morphology and structure of the as-grown samples were investigated using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The crystal property of the stepped nanocombs was characterized using selected area electron diffraction （SAED）. According to the experimental results, the stepped ZnO comb-like structures could be formed by the following steps: the first is a faster growth along [01-10] direction forming the nanobelt stems, and they were enclosed by the ±（0001） side facets and ±（21|-1|-0） top/bottom facets; the second step is the nucleation and growth of the nanorod branches along [0001] direction synchronously, which may be related to the structure characteristic of wurtzite family.2. ZnO nanorods with ～30nm diameter ultra-thin pinheads and ultra-thin nanobelts were synthesized using thiourea solution to etch nanorods and nancombs, which were obtained by conventional thermal evaporation method. EDX measurement was performed in order to determine the components of the nanorods with ～30nm diameter ultra-thin pinheads and ultra-thin nanobelts. The possible formation of the nanorods with ～30nm diameter ultra-thin pinheads and ultra-thin nanobelts were proposed. Finally, the photoluminescence and field emission properties of the sample before and after treatment through Tu solution., indicating that H⁺ ions in the Tu solution not only determine the formation of nanorods with ～30nm diameter ultra-thinpinheads and ultra-thin nanobelts but also play an important role in the improving the physical properties of the obtained samples treated through Tu solution.3. Only （Zn（NO₃）₂·6H₂O） and (C₆H₁₂N₄) were used to successfully synthesize ZnO micro/nanostructures with various morphologies, such as flower-like structures, brush-like structures, nanodisks and nanonunchakus, by a low-temperature hydrothermal route. Parallel experiments were performed by changing growth conditions, such as solution concentration, substrates and "temperature change". The formation processes of the brush pen-like nanostructures which ultimately lead to the formation of ZnO nanonunchakus have been proposed according to the experimental data. Room photoluminescence of the flower- and brush pen-like structures were studied.4. ZnO micro/nano flower-like structures have been synthesized in the high yield using only （ZnCl₂） and （NH₃·H₂O） by a low-temperature hydrothermal route. This chemical solution route has become another promising option for large-scale production of micro-/ nano-scale materials because of its simple, fast, less expensive, low-temperature growth and no pollution to the ambient environment virtues. Compared with other chemical solution methods, only two chemical reagents were used in this route without any other additive, so the fabrication cost was low and the obtained samples have high purity. These ZnO flower-like structures are made up of hexagon plates. Becausing of their high ratio of aspect to volume, they have potential application in chemical sensors, photocatalysts and optical storages and so on. And some as-synthesized samples were charactered using SEM, XRD, EDX and PL. Parallel experiments were performed by changing the solution centration, reaction time, substrates, and pH values. Room photoluminescence of the rose-like structures was investigated and the mechanism of blue and green bands was discussed in brief.更多还原