碳纳米管薄膜的制备及场发射特性的研究

【作者】 田时开；

【导师】 杨中海；

【作者基本信息】 电子科技大学 ， 物理电子学， 2003， 硕士

【摘要】 真空微电子是八十年代后期才发展起来的一门新兴学科,它兼有电真空器件和微电子器件的优点,在场发射平面显示器、微波、毫米波器件和传感器等领域有着重要的应用前景。而这些应用实现的前提就是找到实用的场致发射阴极。碳纳米管的发现,引起了全世界众多科学家的广泛关注,其优异的电学、力学、磁学性能,可以在许多领域得到应用。尤其是它具有的大的长径比,低功函数,良好的导电性和纳米级的尖端,使它能够在相对较低的电压下就能长时间发射电子,因此被认为是一种优良的场致发射阴极,已经应用在诸如扫描电子显微镜和透射电子显微镜等高分辨率电子束器件。并有望在场致发射平面显示器中得到广泛的应用。本文全面介绍了碳纳米管的结构,物性,应用。其中重点介绍了在场致发射平面显示器的应用。并介绍了碳纳米管的各种制备方法及其生长机理。其中,催化热分解法(CVD法)因其设备简单,成本低,反应过程容易控制,生产的碳纳米管质量可以保证,且产量高,成为目前制备碳纳米管的主流方法。本文综合考虑了场发射产生的焦耳热及Nottingham效应,求出了在热平衡时发射体的表面温度,对单壁碳纳米管的场致发射电流进行理论计算,得出单根单壁碳纳米管的发射电流可达微安量级,为实验提供了理论依据。本文通过在镀铝硅片上电镀催化剂粒子和在硅片上真空蒸镀NiCr合金作催化剂,用催化热分解法在硅片上制备出了碳纳米管薄膜,并对其进行了场发射研究,测到的场发射电流可达60。场发射电流密度达到10,轰击荧光屏可产生明亮的光斑。对碳纳米管薄膜用氢气等离子体处理,可使碳纳米管薄膜的开启场强显著降低,对碳纳米管薄膜进行老炼,可使其发射电流得到提高,并使其场发射稳定性增强。实验中,还观察到几种生长方式独特碳纳米管,为碳纳米管的进一步应用打下良好的基础。更多还原

【Abstract】 Vacuum microelectronics is a rising subject. It have both advantages of vacuum device and micro-electronics device, and can be in field emission display, microwave and millimeter-wave device, sensor and so on. But we must find the field-emission cathode that can be used in practicality.The discover of carbon nanotubes attract many scientists’s attention. Carbon nanotubes can be used in many domain due to it have excellent mechanics, electricity and magnetics. Carbon naontubes have a high ratio in length-radius, low workfunction, good electrical conductivity and nanometer tip, it can emit electron long time in low voltage. So it have been considered a good field-emission cathode and have been used in electron beam device such as SEM and TEM. We can expect it have a widely application in field emission display.The paper have a general introduction in structure, physical character and application of carbon nanotubes and emphatic introduce the application in field emission display. The paper have introduced the diversified growth-method and growth-mechanism of carbon nanotubes. Chemical vapor deposition(CVD) is a central method of growth carbon nanotubes. Because the method have a simple equipment and low cost, the reactive process is control easily and carbon nanotubes’s quality are good and the output is high.The paper considered the joule heating and Nottingham effect, caculated the temperature on emitter’s tip and caculated the field-emission current of a single-walled carbon nanotube can reached during simulation and caculate. We electroplated catalyzer on silicon of vaporized Al and vaporized NiCr alloy as catalyzer on silicon, growthed carbon nanotube film on silicon with CVD. The result of field-emission was the field-emission current reached 60and the field-emission current densities reached 10. We watched the bright facula when electron-beam hitting fluorescent-screen. The carbon nanotubes film’s turn on fields have obvious reduce after dealed with H2 plasma and the current have obvious increase after annealed. In experiment, we have watched some nanotubes that growths way were unique. This is a good basement for more application of carbon nanotubes.更多还原