使用改进的原位透射电镜观察技术研究了室温下单晶SI纳米线在聚焦电子束辐照下的结构不稳定性。实验发现辐照区域内单晶SI纳米线外层会优先非晶化且局部径向膨胀,并随辐照剂量增加进一步形成新型3层包裹同轴结构等一系列有趣的变化。传统knOCk-On机制和电子束热效应并不能完全解释上述实验现象,然而利用最近提出的纳米曲率效应和电子束非热激活效应则能得到较好的解释。Structural instability of a single crystal Si nanowire at room temperature under focused electron beam irradiation was investigated by our developed in-situ transmission electron microscopy observation technique.It was observed that a series of intriguing changes such as preferential amorphization at the surface of Si nanowire,local bulging in the radial direction and formation of a novel three layers-packaged coaxial structure of Si nanowire with the increasing of electron doses during the irradiation.The possible mechanism for such phenomena was proposed and further discussed by completely new concepts of nanocurvature effect and energetic beaminduced athermal activation effect,while the current knock-on mechanism and electron beam heating effect seemed inadequate to explain these processes.国家自然科学基金资助项目(11074207); 国家重点基础研究发展计划(973计划)资助项目(2007CB936603); 教育部高等学校博士学科点专项科研基金资助项目(20100121110023); 国家科技计划国际科技合作与交流专项资助项目(2008DFA51230
