原位观察电子束辐照下双壁碳纳米管的不稳定性  

In situ observation of the instability of double-walled carbon nanotubes under electron beam irradiation

作　　者：公会敏[1,2] 朱贤方[1,2,3] 李论雄[1,2] 

机构地区：[1]厦门大学物理系,厦门361005 [2]厦门大学中国-澳大利亚功能纳米材料联合实验室,厦门361005 [3]ARC Centre of Excellence for Functional Nanomaterials,University of Queensland,St Lucia,Brisbane,Queensland 4072,Australia

出　　处：《科学通报》2012年第18期1692-1696,共5页Chinese Science Bulletin

基　　金：国家自然科学基金(11074207);国家重点基础研究发展计划(2007CB936603);教育部高等学校博士学科点专项科研基金(20100121110023);国家科技计划国际科技合作与交流专项(2008DFA51230)资助

摘　　要：室温下利用高分辨透射电子显微镜原位观察了两端固定和一端固定、另一端自由的双壁碳纳米管在电子束辐照下的结构不稳定性.实验发现,在相同辐照条件下,两端固定的双壁碳纳米管首先径向持续均匀收缩,然后局部颈缩,最后在颈缩处断裂;一端固定、另一端自由的双壁碳纳米管轴向长度持续快速缩小,而径向收缩相对缓慢.我们利用最近提出的表面纳米曲率效应和能量束诱导非热激活效应基础上新发展的碳原子"融蒸"和"扩散"机制,对上述电子束辐照下双壁碳纳米管结构不稳定现象进行了全新、合理的解释.The structural instabilities of double-walled carbon nanotubes in two typical environments were investigated in situ by transmission electron microscopy at room temperature. The double-walled carbon nanotube with two fixed ends shrank uniformly in the radial direction, bent locally and finally broke. The double-walled carbon nanotube with one free capped end and the other fixed to a rope of nanotubes shrank quickly and continually in the axial direction and slowly in the radial direction. All experimental phenomena could be well accounted for by the vaporization and diffusion of carbon atoms driven by the surface nanocurvature effect and electron beam-induced athermal activation, which have been underestimated or neglected in existing theoretical descriptions and simulations.

关 键 词：双壁碳纳米管 电子束辐照非热激活 结构不稳定性 表面纳米曲率效应 融蒸和扩散 

分 类 号：TB383.1[一般工业技术—材料科学与工程]