National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
Ultramicroscopy. 2013 Nov;134:185-92. doi: 10.1016/j.ultramic.2013.06.007. Epub 2013 Jul 5.
Energy-filtered scanning confocal electron microscopy (EF-SCEM) is a technique that uses the reduced depth of field of an aberration-corrected transmission electron microscope to provide three-dimensional (3D) compositional information. Using a silicon sample in the <110> orientation, we show that EF-SCEM image data can be recorded that shows lattice resolution in the plane perpendicular to the incident beam direction. The confocal effect is demonstrated through the reduction of the mean intensity as the confocal plane is displaced from the sample mid-plane, unlike optical sectioning in high-angle annular dark-field scanning transmission electron microscopy (STEM). Simulations of the EF-SCEM data show agreement with the experimental data, and allow the interpretability of the data to be explored. The effects of channelling, absorption and delocalisation complicate the quantitative and qualitative interpretation of the data, highlighting the need for matching to simulations. Finally the effects of the finite detector pin-hole aperture size are explored, and we show that the EF-SCEM contrast in the plane perpendicular to the beam direction starts to resemble that of a STEM spectrum imaging experiment as the aperture size increases.
能量过滤扫描共聚焦电子显微镜（EF-SCEM）是一种利用经过像差校正的透射电子显微镜减小景深的技术，以提供三维（3D）成分信息。使用<110>取向的硅样品，我们证明可以记录显示垂直于入射束方向的平面上晶格分辨率的 EF-SCEM 图像数据。与高角度环形暗场扫描透射电子显微镜（STEM）中的光学切片不同，共聚焦效应通过将共聚焦平面从样品中间平面移开时平均强度的降低来证明。EF-SCEM 数据的模拟与实验数据一致，并允许探索数据的可解释性。通道、吸收和离域化的影响使数据的定量和定性解释变得复杂，突出了匹配模拟的必要性。最后，还探索了有限探测器针孔孔径尺寸的影响，我们表明，随着孔径尺寸的增加，垂直于光束方向的平面上的 EF-SCEM 对比度开始类似于 STEM 谱成像实验的对比度。
