Focal-series reconstruction in low-energy electron microscopy
by Thomas Duden, Andreas Thust, Christian Kumpf, and F Stefan Tautz
In low-energy electron microscopy (LEEM) commonly images are encountered 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 grey levels to morphological changes. Through reconstruction of the exit wave, two aspects of LEEM can be addressed: the resolution can be improved by exploiting the full information limit of the microscope and electron phase shifts which contribute to the image contrast can be extracted. In the present study, linear exit wave reconstruction from a through-focal series of LEEM images is demonstrated. As a model system 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 is utilised.
Thomas Duden, Andreas Thust, Christian Kumpf, and F Stefan Tautz: Focal-series reconstruction in low-energy electron microscopy, Microscopy and Microanalysis 20 (2014) 968-973.