透射电子显微学的新进展Ⅱ Z衬度像、亚埃透射电子显微学、像差校正透射电子显微学

Progress of transmission electron microscopy Ⅱ Z-contrast imaging,Sub-angstrom transmission electron microscopy,Aberration-corrected transmission electron microscopy

本文综述了原子分辨率的原子序数衬度成像与原位电子能量损失谱分析、亚埃透射电子显微学、像差校正透射电子显微学和材料的微观结构表征与原位性能测试的最新发展和应用。在配置球差校正器、单色器和高能量分辨率过滤器的FEGTEM STEM中,用相位衬度像 Z衬度成像与原位电子能量损失谱分析方法,在亚埃的空间分辨率和亚电子伏特能量分辨率下,可以研究各种材料的原子尺度界面和缺陷的原子和电子结构、价态、成键和成分等。配置球差校正器后,可明显提高透射电镜的点分辨率,把点分辨率延伸到信息分辨率,同时显著减小衬度离位。随意改变球差系数CS和离焦值Δf,像差校正透射电子显微镜可提供新的成像模式。把特殊的样品杆插入电镜后,可把扫描隧道显微镜(STM)或原子力显微镜(AFM)功能相结合,开展材料的显微结构表征与原位的性能测试,不仅能得到物质的与显微像、成分、衍射有关的信息,同时还可以测量电学、力学性能,也可以研究在外场(温度、应力、电和磁场)作用下材料微观结构演变及结构与性能间的关系。

This paper reviews the progress and application of Z-contrast imaging in combination with electron energy loss spectroscopy, sub-Angstrom transmission electron microscopy, aberration-corrected transmission electron microscopy, and characterization of microstructure and in-situ determination of properties in materials. The atomic and electronic structures, valence state, bonding and composition at interface and defects in materials can be characterized by phase contrast imaging/Z-contrast imaging in combination with electron energy loss spectroscopy at sub-Angstrom spatial resolution and sub-eV energy resolution, using FEG TEM/STEM equipped with monochromator, spherical aberration corrector and filter with high energy resolution. The point resolution was extended to information limit at reduced level of delocalisation with aberration-corrected TEM. The variable spherical aberration C_S combined with variable defocus Δf provides new imaging modes in aberration-corrected TEM. In combination with TEM and STM(or AFM) by special specimen holder, the characterization of microstructure and determination of properties were carried out simultaneously, which can provide comprehensive information, such as image, composition, diffraction, physical and mechanical properties of materials. The evolution of microstructure and structure-property relationships induced by exfernal fields such as electric and magnetic fields, temperature and stress can be studied as well.