Sawada Hidetaka, Allen Christopher S, Wang Shanshan, Warner Jamie H, Kirkland Angus I
Electron Physical Sciences Imaging Centre (ePSIC), Diamond Light Source Ltd, Didcot, Oxford OX11 0DE, UK; Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK; JEOL UK Ltd., Silver Court Watchmead Welwyn Garden City, Herts AL7 1LT, UK; Research acceleration program, Japan Science and Technology Agency, K's Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan.
Electron Physical Sciences Imaging Centre (ePSIC), Diamond Light Source Ltd, Didcot, Oxford OX11 0DE, UK; Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
Ultramicroscopy. 2017 Nov;182:195-204. doi: 10.1016/j.ultramic.2017.06.024. Epub 2017 Jul 5.
The geometric and chromatic aberration coefficients of the probe-forming system in an aberration corrected transmission electron microscope have been measured using a Ronchigram recorded from monolayer graphene. The geometric deformations within individual local angular sub-regions of the Ronchigram were analysed using an auto-correlation function and the aberration coefficients for the probe forming lens were calculated. This approach only requires the acquisition of a single Ronchigram allowing rapid measurement of the aberration coefficients. Moreover, the measurement precision for defocus and two-fold astigmatism is improved over that which can be achieved from analysis of Ronchigrams recorded from amorphous films. This technique can also be applied to aberration corrected STEM imaging of any hexagonal two-dimensional material.
利用从单层石墨烯记录的朗奇图，测量了像差校正透射电子显微镜中探针形成系统的几何像差系数和色差系数。使用自相关函数分析了朗奇图各个局部角子区域内的几何变形，并计算了探针形成透镜的像差系数。这种方法只需要采集一张朗奇图，就能快速测量像差系数。此外，与通过分析从非晶薄膜记录的朗奇图所能达到的精度相比，散焦和二次像散的测量精度有所提高。该技术还可应用于任何六方二维材料的像差校正扫描透射电子显微镜成像。
