Properties of the microscope
Dedicated scanning transmission electron microscope (STEM)
Cold field emission gun (FEG); acceleration
Vacc= 80, 120, 200kV
CEOS corrector system for the probe-forming objective lens
Ultra High Resolution (UHR): beam diameter ≤ 0.1 nm ⇒ resolution < 0.1 nm
High Resolution (HR): beam diameter ca. 0.2 nm
Normal: beam diameter ≥ 0.3 nm
BF and (HA)ADF detectors, secondary electron (SE) detector, Gatan Orius CCD camera, Gatan EEL spectrometer, EDXS detector (EDAX)
Description of the microscope:
Performance and image analysis of the aberration-corrected Hitachi HD-2700C STEM
H. Inada, L. Wu, J. Wall, D. Su, and Y. Zhu, J. Electron Microsc. 58 (2009) 111–122 DOI
Imaging with High Resolution
HAADF-STEM (Z contrast) images of Pt on TiO2
(left) and on C foil (right), respectively. In the right image, isolated bright dots correspond to single Pt atoms. Samples: Makosch, Van Bokhoven (ICB, ETH Zürich).
The structure of Au nanoparticles can be observed in high resolution by phase contrast (PC), Z contrast (ZC), and even by secondary electron (SE) imaging.
Images of ceria nanocrystal along <110> recorded with different detectors: HAADF-STEM (left) and phase contrast mode (center). The contrast in the PC STEM image strongly depends on the focus f as exemplified by the contrast inversion in the images on the right (Δf ≈ 20 nm).
Sample: Baudouin, Copéret (LAC, ETH Zürich).
Nano analysis by EDXS
(a) SE image of RuO2
nanoparticles on SnO2. (b) EDX spectra of the nanoparticles (area 1) coating the support crystals (area 2) proving the coating of SnO2 by RuO2 nanoparticles. Sample: Mondelli, Pérez-Ramírez (ICB, ETH Zürich).
ZC-STEM image of AuPd nanoparticles on titania (left) and EDXS elemental map of Au (right). Particles with a diameter of around 2 nm are still recognizable in the map. Sample: Marx, Baiker (ICB, ETH Zürich).
Catalyst Characterization: TEM vs. STEM - Visualizing Pt Nanoparticles Supported on Cerium Oxide
F. Krumeich and E. Müller, Imaging & Microscopy 12 (2) (2010) 24-27
Characterization of Catalysts in an Aberration-Corrected Scanning Transmission Electron Microscope
F. Krumeich, E. Müller, R. A. Wepf, and R. Nesper, J. Phys. Chem C 115 (2011) 1080–1083 DOI
Surface Properties and Morphology of Supported, Colloid-Derived Gold/Palladium Mono- and Bimetallic Nanoparticles
S. Marx, F. Krumeich, and A. Baiker, J. Phys. Chem. C 115 (2011) 8195-8205 DOI
Characterization of AuPd Nanoparticles by Probe-Corrected Scanning Transmission Electron Microscopy and X-Ray Absorption Spectroscopy
F. Krumeich, S. Marx, A. Baiker, and R. Nesper, Z. anorg. allg. Chem. 637 (2011) 875–881 DOI
Phase-Contrast Imaging in Aberration-Corrected Scanning Transmission Electron Microscopy
F. Krumeich, E. Müller, and R. A. Wepf, Micron 2013, 49, 1-14 DOI