Chromatic Aberration Correction for Atomic Resolution TEM Imaging from 20 to 80 kV
Chromatic Aberration Correction for Atomic Resolution TEM Imaging from 20 to 80 kV
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DOI：
10.1103/physrevlett.117.076101
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发表时间：
2016-08-09
影响因子：
8.6
通讯作者：
Kaiser, Ute
中科院分区：
文献类型：
--
作者：
Linck, Martin;Hartel, Peter;Kaiser, Ute
薄原子和轻原子材料的透射电子显微镜的原子分辨率需要严格降低束能量以减少敲击损伤。然而，与此同时，色差极大地降低了 TEM 图像的分辨率。在SALVE项目的框架内，我们推出了一种新开发的C-c/C-s校正器，能够在20至80 kV的加速电压范围内校正色差和球差。校正器可以校正高达五阶的轴向像差以及主要的离轴像差。在整个电压范围内，可以调整来自轻原子的微弱信号的最佳相衬成像条件，以获得至少 55 mrad 的光学孔径。该孔径内的信息传输不再受到色差的限制。我们使用石墨烯和二硫化钼的 30 kV 相衬 TEM 图像示例展示了显微镜的性能，显示了与图像计算相匹配的前所未有的对比度和分辨率。
Atomic resolution in transmission electron microscopy of thin and light-atom materials requires a rigorous reduction of the beam energy to reduce knockon damage. However, at the same time, the chromatic aberration deteriorates the resolution of the TEM image dramatically. Within the framework of the SALVE project, we introduce a newly developed C-c/C-s corrector that is capable of correcting both the chromatic and the spherical aberration in the range of accelerating voltages from 20 to 80 kV. The corrector allows correcting axial aberrations up to fifth order as well as the dominating off-axial aberrations. Over the entire voltage range, optimum phase-contrast imaging conditions for weak signals from light atoms can be adjusted for an optical aperture of at least 55 mrad. The information transfer within this aperture is no longer limited by chromatic aberrations. We demonstrate the performance of the microscope using the examples of 30 kV phase-contrast TEM images of graphene and molybdenum disulfide, showing unprecedented contrast and resolution that matches image calculations.