Fu-Rong Chen1, Dirk Van Dyck2, Christian Kisielowski3, Stig Helveg4, Hector Calderon5 and Angus Kirkland6
- Dept. of Engineering and System Science, National Tsing Hua University, Taiwan
- EMAT, Dept. of Physics, University of Antwerp, Belgium
- Molecule Foundry, Berkeley, USA
- Haldor Topsoe, Kongens Lyngby, Denmark
- Depto. Física, ESFM-IPN, Mexico
- Dept. of Materials Science and Engineering, Oxford University, UK
Resolution and sensitivity of the latest generation aberration-corrected Transmission Electron Microscopes allow imaging the vast majority of single atoms from the Periodic Table of Elements with sub-Ångstrom resolution and determining their locations in an image plane with a precision that exceeds the 1.9 pm wavelength of 300 kV electrons. Further progress that exploits this ability requires addressing at leading-edge: (1) there is the need to recover structural information in three dimensions from the two dimensional projection (2), a most noticeable bottleneck to reconstruct 3D structural information are electron beam-induced sample alterations , since a large accumulated electron dose in the range of 104 – 105 e/Å-2s-1. is typically required to achieve a needed resolution around one Ångstrom and single atom sensitivity. We present, in the talk, a general tomographic method to recover the 3D shape of a crystalline particle from high-resolution images of a single projection without need for sample rotation. The method is compatible with low dose rate electron microscopy, which improves on signal quality while minimizing electron beam-induced structure modifications even for small particles or surfaces. We apply it to MoS2, NiO, CeO2, Ge1, Au1 and MgO1 particles and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances. The algorithm of 3D reconstruction method at atomic resolution is outlined followed.
Determination of the true “z” height (focus) of the exit surface of a column from an image plane with the maximum peak intensity (MPI) criterion by wave propagation along “defocus circles” as shown in Fig. 11.
Refining the “z” height using the Big-Bang scheme2.
Correcting the focus of each column wave by back-propagation, and bring the exit wave back to “mass” circle1.
Measuring the phase of the normalized focus corrected wave (at mass circle) from the center of mass circle. The column mass is given by the phase angle θ’ between the normalised focused corrected wave and the vacuum wave. See Fig. 1
The fig. 2 shows for MoS2 and CeO2 nanoparticles the phases of electron exit wave functions that are used to reconstruct the corresponding reconstructed atomic resolution tomograms.
1.Chen, F.-R., Van Dyck, D. & Kisielowski, C. In-line three-dimensional holography of nanocrystalline objects at atomic resolution. Nat. Commun. 7, 10603 (2016).
2. Dirk Van Dyck*,Joerg R. Jinschek,Fu-Rong Chen* . ‘Big-Bang’ tomography as a new route to atomic-resolution electron tomography. Nature, 486, (2012) p.243-246. (SCI).
Christian Kisielowski is supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, which also operates the TEAM0.5 Microscope in the Molecular Foundry that was used to acquire all images. D. Van Dyck acknowledges the financial support from the Fund for Scientific Research – Flanders (FWO) under Project nos. VF04812N and G.0188.08 . F.-R. Chen would like to thank the support from NSC 96-2628-E-007-017-MY3 and NSC 101-2120-M-007-012-CC1
To cite this abstract:Fu-Rong Chen; Atomic Resolution Tomography of Nanoparticles Reconstructed from Exit Wave. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/atomic-resolution-tomography-of-nanoparticles-reconstructed-from-exit-wave/. Accessed: February 28, 2020
EMC Abstracts - https://emc-proceedings.com/abstract/atomic-resolution-tomography-of-nanoparticles-reconstructed-from-exit-wave/