碳纳米管/聚四氟乙烯复合材料场发射特性研究

【作者】 张文锋；

【导师】 杨中海；

【作者基本信息】 电子科技大学 ， 物理电子学， 2006， 硕士

【摘要】 碳纳米管作为一种新型的纳米材料,由于其独特的物理和化学性能以及在诸多领域的应用前景,自发现以来便吸引了众多学者的广泛关注。因为碳纳米管及其复合材料具有优异的场发射特性,因此在真空场发射器件尤其是平板显示器方面具有巨大的应用前景。由于真空场发射器件对于器件内部真空度的要求很严格,因此场发射阴极材料的真空性能非常重要。而目前国内外研究的碳纳米管复合材料场发射阴极较少考虑满足器件对其高真空的要求。本文研究制作了碳纳米管/聚四氟乙烯复合材料场发射阴极,研究了其场发射特性和实际应用优势。主要内容为以下几个方面:1.本文通过化学气相沉积法制备了碳纳米管,分析了碳纳米管的生长机理。然后采用酸性双氧水溶液处理和空气氧化法相结合的方法对碳纳米管粗品进行了提纯。通过反复实验优化制备实验参数,并确定了空气氧化提纯的温度和时间。2.采用物理共混的方法将碳纳米管与聚四氟乙烯浓缩分散液相混合制备了碳纳米管/聚四氟乙烯复合材料。讨论了复合材料中碳纳米管不同质量比组成对复合材料阴极场发射特性的影响,确定了最佳的碳纳米管质量比组成。通过表面刻划的方法对碳纳米管/聚四氟乙烯复合材料阴极薄膜进行了表面处理,改善和提高了碳纳米管复合材料阴极的场发射特性。3.为了研究场发射阴极材料对场发射真空器件内部真空度影响的问题,设计二极电极结构,分别以碳纳米管/聚四氟乙烯和碳纳米管/环氧树脂两种复合材料作为场发射阴极,进行了真空封装,制成了静态的真空系统。通过对比测试,研究了两种复合材料阴极在静态真空系统中的场发射特性,比较了两者在不同场发射电流密度时的电流稳定性,以及随着封装后时间的增长对静态真空系统场发射性能的影响。证实了碳纳米管/聚四氟乙烯复合材料作为场发射阴极更有利于真空度的维持,应用在真空场发射器件中更具有优势。最后总结了本文的实验成果,展望了碳纳米管/聚四氟乙烯复合材料场发射阴极以及场发射平板显示器今后的应用研究工作。更多还原

【Abstract】 As a new kind of nanomaterial, carbon nanotube (CNT) has been widely attended and studied by many scientists from the beginning since it was discovered because of its unique physical and chemical performance and its application foreground. Thanks to the excellent field-emission property, CNT and its composites have tremendous application potential in the area of field-emission vacuum devices, especially panel display.Because field-emission devices have strict requirement for the vacuum environment, the vacuum performance of the field-emission cathode was very significant. In this thesis, carbon nanotubes/polytetrafluoroethylene (CNTs/PTFE) composite materials for field-emission cathode were prepared, its field-emission property and the predominance of the application in field-emission devices were studied. The main contents in this paper were as follows:1. CNTs were synthesized by chemical vapor deposition (CVD) method, the mechanism of CNTs growth was analyzed. Then the methods of acidic H2O2 solution disposal and air oxidation were used to purify CNTs. Experimental parameter was optimized in synthesizing CNTs process and the temperature and time for the air oxidation were ascertained.2. CNTs/PTFE composite materials were prepared by using physical mixing method, purified CNTs and PTFE latex were as original materials. The influence for the field-emission property of CNTs/PTFE composite material with different mass content of CNTs were discussed and optimal CNTs mass content were ascertained. It was proved that by using the method of surface score for CNTs/PTFE cathode, the field-emission property was improved.3. To study the influence of the field-emission cathode materials for the vacuum environment of the field-emission devices, ambipolar electrode configuration was designed in this paper. CNTs/PTFE and CNTs/epoxy composite materials were used as field-emission cathode and the two electrode configurations were encapsuled into a static vacuum system respectively. By contrastive testing, the field-emission properties更多还原