【作者】 郁可；

【导师】 朱自强；

【作者基本信息】 华东师范大学 ， 无线电物理， 2004， 博士

【摘要】 纳米材料与结构由于和相应的体材料相比，具有许多独特的性能和诱人的应用前景，引起了各国研究人员的极大兴趣和关注。目前，最具实用化和市场化的应用领域是利用某些纳米材料和结构的优异电子场发射性能来制作场发射平板显示器。从而场发射阴极材料也就成为整个纳米材料研究的热点之一。本论文在国家杰出青年、自然科学基金(Nos．69925409、10374027)和上海市科委重点科技项目(No．015211066)的联合资助下，对三种纳米材料、结构，即：纳米碳管、纳米硅和氧化锌纳米结构的薄膜制备、微结构和其电子场发射性能进行了深入研究。主要结论和创新性成果如下： 1) 采用丝网印刷和电泳淀积方法大面积制备了碳纳米管薄膜，考察了退火处理和氢等离子体处理(HP)工艺对碳纳米管薄膜的影响，发现退火和HP处理可以改善碳纳米管薄膜的场发射性能，并使其开启电场、阈值电场和发射点密度分别达到1.1、5.3 V／μm和10~5／cm~2。氢HP处理后一种碳纳米管的新结构被发现。通过SEM、TEM、HRTEM、Raman谱、XPS和FTIR谱研究了氢等离子体处理前后碳纳米管薄膜的表面形貌和微结构特征，讨论了HP处理后的碳纳米管结构变化机制以及其电性质和场发射性能转变的原因。 2) 首次对碳纳米管和纳米铁粉共球磨进行研究。通过SEM和TEM对球磨后碳纳米管的表面形貌和微结构进行了考察。实验结果显示球磨8小时后原碳纳米管的封闭端头被打开，并在纳米管壁上产生了扭曲变形的石墨层。球磨后碳纳米管薄膜的电子场发射性能得到了很大的改善，开启电场和阈值电场可分别达到2.1 V／μm和5.6 V／μm，发射发射密度可达到10~4／cm~2。 3) 首次利用可溶于有机溶剂的MWNT-ODA，通过旋涂技术制备了均匀的碳纳米管薄膜，通过电子显微镜和显微Raman谱表征了HP处理前后的MWNT-ODA薄膜，发现HP处理后的MWNT-ODA薄膜表面被一层碳纳米颗粒覆盖，并且其场发射性能得到了极大改善，开启电场和阈值电场分别达到0.5 V／μm和3.2 V／μm，发射点密度可达到10~3～10~4／cm~2。 4) 首次采用电化学阳极氧化方法在P型(100)硅片上成功制备了颗粒尺寸均匀、 摘要............脚口旦鱼鱼鱼鱼旦，...排列紧密、晶向一致的单晶纳米硅薄膜。并对不同颗粒大小、不同膜厚和氢等离子体处理前后样品的电子场发射性能进行了测试，实验结果表明，这种纳米硅薄膜具有较低的开启电场，发射电流和发射点密度适中，是一种有潜力的场发射阴极材料。 5)采用热蒸发技术成功制备了大量四角状和线状ZnO纳米结构。该制备工艺不需要真空和使用其它金属催化剂和添加济，适用于工业化生产。首次研究了这些四角状ZnO纳米结构的电子场发射特性。实验发现其开启电场为1 .SV/禅m与多壁碳纳米管相当，是一种可替代碳纳米管的有巨大应用潜力的场发射阴极材料。 6)首次采用气相输运方法在有金属填充的多孔硅、纳米硅衬底上制备了ZnO纳米棍、纳米带和纳米柱。通过催化剂和衬底结构图形化实现了ZnO材料的图形化和选区生长。场发射测试表明，这些样品具有较低的开启电场和阂值电场，较高的发射点密度以及均匀一致的发射像。更多还原

【Abstract】 Nanomaterials and nanostructures have received great interests due to their peculiar and fascinating properties, superior to their bulk counterparts for applications. To date, the most possible practicality and marketability of the nanomaterials are the field emission display manufacture that utilizes the excellent field emission property of some nanomaterials and nanostructures. The cold cathode is one of the focus of the nanomaterials study even the whole nanotechnology research. Therefore, supported by the National Natural Science Foundation (Nos. 69925409, 10374027) and Shanghai science and technology item (No. 015211066) the preparation processes, microstructures, and electron field emission properties of carbon nanotube films, silicon nanocrystallite films, and zinc oxide nanostructures were investigated in this work. Main concludes and innovative results are listed as follow:1) Large-scaled multi-walled carbon nanotube (MWNT) films have been fabricated using screen-printing and electrophoresis deposition technique. The effects of annealing and hydrogen plasma (HP) treatment on MWNT films were investigated, it is found that annealing and hydrogen plasma treatment could greatly improve the field emission properties of MWNT films. For the HP treated MWNT films, the low turn-on field of 1.1V/um, threshold field of 5.3 v/ u m, and high emission site density of 105/cm2 have been achieved respectively. A novel structure of HP treated MWNT was found, and the surface morphology and microstructure features of the films before and after HP treatment were investigated in terms of SEM, TEM, HRTEM, Raman, XPS and FTIR. The conversion mechanism of the HP treated carbon nanotube structures and the origin for the change of the electronic and field emission characteristics of the MWNT films were discussed.2) The effects of grinding for different time in a vibrating mill on the mixture of Fe nanopowder and multi-walled carbon nanotubes were studied. The morphology and structures of the ground MWNTs were investigated using SEM and TEM. The results show that a part of closed ends of the tubes were broken and graphite layer of some nanotubes were tortured while ground for 8h. The field emission measurement results indicated theimprovement of field emission properties of the ground MWNT films. The turn-on field of 2.1 V/ u m, threshold field of 3.6 V/ u m, and emission site density of 104/cm2 were obtained.3) Homogeneous MWNT films have been fabricated by a spin-coating method using the soluble octadecylamine (ODA) modified multi-wall carbon nanotubes. The characterization, by means of electron microscopy and micro-Raman spectroscopy, shows that the surfaces of MWNTs-ODA with HP treatment are covered by the carbon nanoparticles. The field emission tests indicate that the treated MWNTs-ODA film has low turn-on field of 0.5 V/ u m , threshold field of 3.2 V/um, and high emission site density of 103~104/cm2.4) Compact aligned, (100)-orientated silicon nanocrystallite films were fabricated by the anodic etching method. Field emission measurements of the films with different grain sizes and thicknesses were performed before and after HP treatments respectively. The experimental results demonstrated that the SiNC films with lower turn-on field and threshold field could be used for flat panel displays.5) Tetrapod-like and wire-like ZnO nanostructures were successfully synthesized by a thermal evaporation method. In our method, no metal catalyst, graphite additive, and vacuum condition were used. It could be important for large-scale industrialization. The field emission characteristics of the ZnO nanostructures were studied for the first time. The turn-on field is found to be as low as 1.8 V/ u m, equivalent to that of MWNTs. Our results demonstrated that tetrapod-like ZnO nanostructures have potential application in the field of vacuum electron devices.6) ZnO nanorods, nanobelts, and nanopillars were prepared on the metal-filled porous silicon and nanocrystallite silicon by a vapor phase transport m更多还原