碳纳米管电子束加工过程中非均匀收缩不稳定性机制研究

The unique tube-like structure of carbon nanotube and its potential applications in nanodevices has attracted a lot of research attention. Nevertheless, in the existing literature, there only were some qualitative researches on the radial shrinkage of carbon nanotube during the electron beam irradiation, the non-uniform (or not keeping same velocity) radial shrinkage and non-uniform shrinkage at different curvature site of tube induced by nano curvature effect of carbon tube were neglected. And, these researches are almost all considered and explained based on the classic knock-on mechanism. The project herein is proposed to further systematically investigate effect of electron beam irradiation on carbon nanotube via in-situ high voltage transmission electron microscope observation technique. Arming to break through the existing knock-on mechanism and concept, the project is to observe interaction of unfocused energetic electron beam with carbon nanotube with different curved shapes. The project research will be focused on nano-curvature effect of the tube and athermal activation effect of the beam irradiation as generally neglected in the current literature as well as resultant structural change (i.e., athermal atom “diffusion” or “evaporation”). The final goal of the project is to provide credible parameters and scientific basis for stability, manufacture, processing, and electron microscope observation of carbon nanotube-based devices of new generation.

碳纳米管由于其独特的管状纳米结构及其潜在纳米器件应用备受关注，但现有文献中利用电子束辐照研究碳纳米管不稳定性过程中仅局限于碳管径向收缩等定性研究，而忽视了碳管纳米曲率效应导致的径向收缩过程中的非均匀性（或非匀速）以及本身不同曲率结构处的非均匀收缩，而且这些研究几乎都是基于传统knock-on机制来考虑和解释的。本项目拟采用高压透射电镜原位观察技术，进一步开展电子束对碳纳米管辐照效应系统深入研究。我们拟突破现有文献中knock-on机制和概念，来观察高能非聚焦电子束与不同形态单壁和多壁碳纳米管独特管状结构的交互作用，重点研究碳管非均匀收缩过程中文献所忽略的纳米曲率效应和电子束非热激活引起的原子“融蒸”和“扩散”机制。以期为确定新一代碳纳米管器件稳定性、制备、电子束加工工艺及其电镜检测提供可靠参数和科学依据。

碳纳米管由于其独特的管状纳米结构及其潜在纳米器件应用备受关注，但现有文献中利用电子束辐照研究碳纳米管不稳定性过程中仅局限于碳管径向收缩等定性研究，而忽视了碳管纳米曲率效应导致的径向收缩过程中的非均匀性（或非匀速）以及本身不同曲率结构处的非均匀收缩，而且这些研究几乎都是基于传统knock-on机制来考虑和解释的。本项目采用高压透射电镜原位观察技术，进一步开展电子束对碳纳米管辐照效应系统深入研究。突破现有文献中knock-on机制和概念，观察了高能非聚焦电子束与不同形态单壁和多壁碳纳米管独特管状结构的交互作用，发现文献所忽略的纳米曲率效应和电子束非热激活引起的原子“融蒸”和“扩散”机制在碳管非均匀收缩过程中起重要作用，决定碳管的最终结构和形态。为确定新一代碳纳米管器件稳定性、制备、电子束加工工艺及其电镜检测提供了可靠参数和科学依据。