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在碳纳米管场发射过程中,碳纳米管烧毁现象一直是影响碳纳米管场发射能力及稳定性的重要因素。目前,对碳纳米管烧毁机理研究较少。本文采用化学气相沉积原位生长技术制备了不同形貌的碳纳米管阵列。通过对不同形貌的碳纳米管场发射测试过程及碳纳米管烧毁前后形貌的研究,得出碳纳米管烧毁机理主要有三种。一是碳纳米管高度不均匀和碳纳米管本身的缺陷等原因引起了电场局域现象,这种局域场强使得碳纳米管局域温度过高而引起碳纳米管烧毁;二是碳纳米管吸附和脱附造成碳纳米管烧毁;三是碳纳米管与基片间存在较高的接触电阻而产生较高的焦耳热,使得碳纳米管烧毁。本文不仅给出了碳纳米管烧毁机理,还给出了相应的解决方案。这对碳纳米管场发射阴极的研究具有一定的意义。
During the field emission of carbon nanotubes, the phenomenon of carbon nanotubes burning down is always an important factor that affects the field emission capability and the stability of the carbon nanotubes. At present, there are few researches on the burning mechanism of carbon nanotubes. In this paper, different morphologies of carbon nanotube arrays were prepared by chemical vapor deposition in situ growth technology. Through the study of the field emission test of carbon nanotubes with different morphologies and the morphologies of carbon nanotubes before and after burning, it is concluded that there are mainly three kinds of carbon nanotubes burning mechanism. First, the highly uneven carbon nanotubes and carbon nanotubes and other defects caused by the local electric field phenomenon, this local field strength makes carbon nanotubes caused by excessive local temperature carbon nanotubes burned; the second is carbon nano Tube adsorption and desorption caused by carbon nanotubes burned; Third, there is a high contact resistance between the carbon nanotubes and the substrate resulting in higher Joule heat, making the carbon nanotubes burned. This paper not only gives the carbon nanotubes burn mechanism, but also gives the corresponding solutions. This study of carbon nanotube field emission cathode has a certain significance.