Duden Thomas, Thust Andreas, Kumpf Christian, Tautz F Stefan
1Peter Grünberg Institut (PGI-3),Forschungszentrum Jülich,52425 Jülich,Germany.
2Ernst Ruska-Centrum (ER-C) and Peter Grünberg Institut (PGI-5),Forschungszentrum Jülich,52425 Jülich,Germany.
Microsc Microanal. 2014 Jun;20(3):968-73. doi: 10.1017/S1431927614000403. Epub 2014 Apr 9.
In low-energy electron microscopy (LEEM) we commonly encounter images which, beside amplitude contrast, also show signatures of phase contrast. The images are usually interpreted by following the evolution of the contrast during the experiment, and assigning gray levels to morphological changes. Through reconstruction of the exit wave, two aspects of LEEM can be addressed: (1) the resolution can be improved by exploiting the full information limit of the microscope and (2) electron phase shifts which contribute to the image contrast can be extracted. In this article, linear exit wave reconstruction from a through-focal series of LEEM images is demonstrated. As a model system we utilize a heteromolecular monolayer consisting of the organic molecules 3,4,9,10-perylene tetracarboxylic dianhydride and Cu-II-Phthalocyanine, adsorbed on a Ag(111) surface.
在低能电子显微镜（LEEM）中，我们经常会遇到这样的图像，除了振幅对比度外，还显示出相位对比度的特征。这些图像通常通过跟踪实验过程中对比度的变化，并为形态变化分配灰度级来进行解释。通过重建出射波，可以解决LEEM的两个方面的问题：（1）利用显微镜的全信息极限可以提高分辨率；（2）可以提取对图像对比度有贡献的电子相移。在本文中，展示了从LEEM图像的焦深系列进行线性出射波重建。作为一个模型系统，我们使用了由有机分子3,4,9,10-苝四羧酸二酐和铜（II）-酞菁组成的异分子单层，吸附在Ag(111)表面。
