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MI: Fachverband Mikrosonden

MI 1: Analytical Electron Microscopy: SEM and TEM-based Material Analysis

MI 1.9: Vortrag

Montag, 20. März 2017, 12:45–13:00, MER 02

Quantitative high-resolution off-axis electron holography of 2D materials — •Florian Winkler^{1, 2}, Juri Barthel^{1, 3}, Sven Borghardt⁴, Amir H. Tavabi^{1, 2}, Emrah Yucelen⁵, Beata E. Kardynal⁴, and Rafal E. Dunin-Borkowski^{1, 2} — ¹Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich, Germany — ²Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich, Germany — ³Gemeinschaftslabor für Elektronenmikroskopie (GFE), RWTH Aachen University, D-52074 Aachen, Germany — ⁴Peter Grünberg Institute 9 (PGI-9), Forschungszentrum Jülich, D-52425 Jülich, Germany — ⁵FEI Company, Achtseweg Noord 5, Eindhoven 5600 KA, The Netherlands

Usually, phase information in conventional transmission electron microscopy (TEM) is lost. A fully recorded electron wave function with its amplitude and phase would allow for post-acquisition removal of residual aberrations and thus an accurate quantitative description of a material’s atomic structure.

Here, we present electron wave functions reconstructed from high-resolution electron holograms of two-dimensional WSe₂. We show that a very precise knowledge of microscope and sample-related parameters, such as image spread, Debye-Waller factor and specimen tilt, can be obtained by comparing experimental wave functions with simulations. Furthermore, we are able to remove residual aberrations from the experimental data, which enables a quantitative description of the atomic structure, including the detection of structural defects.