Annular Dark-Field Imaging

It is sometimes argued that - by reciprocity - STEM and HRTEM can perform similar tasks since a STEM can be thought of as a HRTEM with detector and electron source being exchanged if the detector is a point detector on the optical axis . Indeed, bright field -and annular dark field imaging can be executed in either a STEM or a HRTEM as shown for the latter in Figure 4. ... 

Figure 4. Bright - and annular dark field image of a CdSe tetrapod and an adjacent gold particle recorded in a TEM. The line profiles demonstrate Z-contrast in the dark field image.

A recent flurry of activity in aberration correetion has been partially prompted by the ease of reliable precision lens control offered by the personal computer and the computer-aided tuning of complex lens systems. Several demonstration models have been developed for TEM [3.44], SEM [3.45] and STEM [3.46] that illustrate the general validity of the eoneept. The application of spherical aberration correctors is most effective in dedieated STEM because it suffers less from chromatic aberration due to a lack of post-specimen lenses (for example for high-angle annular dark-field imaging). 

Fig. 10. a Bright-field (BF) images of mesoporous silica with Pd Ru particles, b HAADF (high-angle annular dark field) images of mesoporous sihca with Pd Ru particles. c,d Electron-stimulated X-ray emission images prove that particles are intact. Reprinted with permission from [74]. Copyright (2001) American Chemical Society... 

Figure S.15 Application of hyperspectral imaging to individual particles in supported metal catalysts. Annular dark-field image (top left) acquired from an Au-Pd/TiOj catalyst and the corresponding XEDS elemental maps Au-M (top left), Pd-L (middle left), O-K (middle right), and Ti-K (bottom left). Also shown is a...

Figure 9 Nanostructured multicompartment cylinders, (a and b) Bright-field TEM images. Dark regions represent polypentafluorostyrene-chain-rich areas, (c and d) High-angle annular dark-field images of cylindrical micelles with internal phase-separated cores, (e) Cryogenic TEM image of uniform cylindrical micelles at 40% water/THF solution, (f) Cryogenic TEM image of cylindrical micelles with internal phase-separated cores at 67% water/THE solution. Chemical structures and schematic illustration of the formation of multicompartment cylinders (bottom). Reproduced with permission from...

Fig. 2 Montage of 2.5% Au-2.5% Pd/C catalyst particles Annular Dark Field image of the catalyst particles (column-1), Au La X-ray Energy Dispersive Spectroscopic map (column-2), Pd La Energy Dispersive Spectroscopic map (column-3), and RGB overlays (red, C green, Au blue, Pd) of the catalysts (column-4). The figure is taken from ref. 25 with the permission...

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