Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Topical Session: TEM-Symposium - HR Imaging & Analytic I
MM 17.3: Vortrag
Dienstag, 12. März 2013, 11:00–11:15, H4
Investigating the potential of determining the 3D structure of nanoparticles from through focus series of HRTEM images — Alexander Surrey1,2, Darius Pohl1,2, Ludwig Schultz1,2, and •Bernd Rellinghaus1 — 1IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany. — 2TU Dresden, Institut für Festkörperphysik, D-01062 Dresden, Germany
The acquisition of through focus series of HRTEM images allows for a determination of the complex electronic exit wave function (EWF) which is a result of modifications of the incoming electron wave through multiple scattering processes within the sample. On the other hand, using the channeling theory in combination with the vacuum propagator to control the defocus in principle allows for a quantitative reconstruction of the full 3D structure of the specimen from the amplitudes and phases of the EWF through Argand plots. In order to explore the applicabitity of this approach we have calculated the EWF for a 4 nm Au octahedron supported by 5 nm of amorphous carbon by means of a multi-slice algorithm and subsequently back-analysed the likewise obtained EWF with the above mentioned approach to reconstruct the 3D structure of the model particle. We find that such a reconstruction should indeed be possible under ideal microscopy conditions. However, taking into account realistic limitations of the imigang process even for the case of state-of-the-art aberration-corrected microscopy leads to a collapse of the channeling circle thereby impeding an unambiguous reconstruction of the structure. These theoretical findings are confirmed by the results of likewise conducted experiments.