HRTEM and Diffraction of Gold (Au) Particles & Single Crystals
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Figure 4171a (a) shows a HRTEM image of an Au particle on a very thin amorphous W/WO2 film and (b) shows that Fourier transformation of the image (a) produced diffractogram. The additional spots from hexagonal fiberoptic array in (b) were due to inadequate gain normalization.

HRTEM image of an Au particle on a very thin amorphous W/WO2 filmFourier transformation of Au particle

Figure 4171a. (a) HRTEM image of an Au particle on a very thin amorphous W/WO2 film and (b) Fourier transformation of (a). [1]

The extent of information transfer and the spatial resolution can be calculated by frequency space obtained from Young’s fringes produced by an image shift during imaging exposure. Figure 4171b shows the Fourier transforms of HRTEM (high-resolution TEM) images of gold (Au) nanoparticles on an amorphous carbon film. A monochromator was installed in the TEM system. When the monochromator was turned off, the Young’s fringes extended only to about 70 pm. When the monochromator was turned on and thus the effect of chromatic aberration was reduced, the Young’s fringes extended beyond 50 pm (red circle) in all directions, reflecting that this microscope with the monochromator has 50 pm spatial resolution.

Young’s Fringes Produced by TEM Image Shift

Figure 4171b. HRTEM performance demonstrated by Young’s fringe experiments with gold nanoparticles on a carbon film: (a) With monochromator turned off, the Young’s fringes extended to about 70 pm; (b) With monochromator turned on, the Young’s fringes extended beyond 50 pm. The inset line traces are obtained from the areas outlined in green and red boxes [2].

Crystal Au has cubic structure. Its lattice parameter is 0.407 nm so that the (220) lattice spacing (see page3547) can be given by,

           Diffraction Patterns & Crystallography of Silicon ------------------- [4171]

Table 4171 lists the angles (2θB) between the direct beam 000 and diffracted beams as well as the lattice spacings for Au at accelerating voltages of 100, 200, 300 and 400 kV.

Table 4171. Angles (2θB) between the direct beam 000 and diffracted beams as well as the lattice spacings for Au at accelerating voltages of 100, 200, 300 and 400 kV.
hkl
Angle (mrad)
Lattice spacing (nm)
100 kV 200 kV 300 kV 400 kV
111 15.75 10.68 8.38 6.98 0.2350
200 18.18 12.33 9.68 8.06 0.2035
220 25.71 17.44 13.69 11.40 0.1439
113 30.15 20.45 16.05 13.36 0.1227
222 31.49 21.36 16.77 13.96 0.1175
400 36.36 24.67 19.36 16.12 0.1018
133   26.88 21.10 17.56 0.0934

 

[1] M. A. O’Keefe, C. J. D. Hetherington, Y. C. Wang, E. C. Nelson, J.H. Turner, C. Kisielowski, J. -O. Malm, R. Mueller, J. Ringnalda, M. Pane, and A. Thust, Sub-Ångstrom high-resolution transmission electron microscopy at 300 keV, Ultramicroscopy 89 (2001) 215–241.
[2] C. Kisielowski, B. Freitag, M. Bischoff, H. van Lin, S. Lazar, G. Knippels, P. Tiemeijer, M. van der Stam, S. von Harrach, M. Stekelenburg, M. Haider, S. Uhlemann, H. Müller, P. Hartel, B. Kabius, D. Miller, I. Petrov, E. A. Olson, T. Donchev, E.A. Kenik, A. R. Lupini, J. Bentley, S.J. Pennycook, I. M. Anderson, A.M. Minor, A.K. Schmid, T. Duden, V. Radmilovic, Q. M. Ramasse, M. Watanabe, R. Erni, E.A. Stach, P. Denes, and U. Dahmen, Detection of Single Atoms and Buried Defects in Three Dimensions by Aberration-Corrected Electron Microscope with 0.5-Å Information Limit, Microsc. Microanal. 14, 469–477, 2008.

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