学无止“镜”、微观之美——透射电镜下凝聚态物质原子尺度解析和操纵
活动时间： 05月30日10时00分
地 点 ： 理科楼2号楼A302
讲座内容：
Using the various advanced transmission electron microscopy (TEM) techniques, direct atomic-scale structure-property information can provide unique insights into the nanomaterials, in both ex-situ and in-situ ways. More than that, we can fabricate and recover nanostructures using the high-energy electron beam (e-beam) in the TEM.
Besides the structural information, the TEM can provide also the physical properties. The spontaneous polarization for Wurtzite ZnSe has been quantified using the combination of the aberration-corrected atomic-scale HAADF-STEM imaging, nano-scale electron holography and the ab initio calculation. Furthermore, the atomic-scale polarization field across InAs polytype interfaces has been determined by the aberration-corrected atomic-scale HAADF-STEM imaging directly [3]. By the way, the atomic configurations at InAs partial dislocation cores associated with Z-shape faulted dipoles have been revealed.
The dynamical structural revolution can also be provided dynamically when we manipulate the nanomaterials in-situ in the TEM. For example, we can modify the Wurzite to Zinc Blende structure in InAs nanowires. When the gold nanowires was pulled in the TEM, the in-situ experiments show that the dislocations produce from the surface and glide through the nanowires and then disappeared at another surface. The necking phenomenon has also been observed. After the fracture, the nanowires may experience an FCC to BCT phase transformation. If pulled by different direction, the dislocations will form a small angle grain boundary. After the fracture, the dislocations move out to the surfaces immediately and the grain boundary will disappear. If Li2O nanowires are being pulled in the TEM with the electron beam on, they will show much more plasticity with the electron beam assistance, which means that the high-energy e-beam can modify the structure of the nanomaterials.
Furthermore, we use the high-energy e-beam to fabricate and recover the nanostructures in-situ in the TEM rather than routine fabrication outside the TEM. The faceted nanopores can be drilled along various axes and can be recovered atomically in the TEM as magnesium as an example.
主讲人介绍：
王建波，武汉大学物理科学与技术学院教授、博士生导师、副院长、教学指导委员会主任，武汉大学电子显微镜中心执行主任，中国电子显微学会常务理事、物理与材料专业委员会委员，湖北省电子显微镜学会理事长。获教育部“新世纪优秀人才支持计划”（2007年）、湖北省青年杰出人才基金资助（2005年）；获湖北省自然科学一等奖（2005年，排名第4）等。
目前主要从事物质超微结构的电子显微学表征及相关计算研究。主持和参加项目包括4项国家自然科学基金、1项973纳米专项、1项教育部“新世纪优秀人才支持计划”基金、1项湖北省青年杰出人才基金、1项教育部留学回国人员启动基金等。发表科研论文一百多篇。
发布时间：2015-05-29 14:15:24