NEW APPROACH FOR SIMULTANEOUS ORIENTATION AND 3-DIMENSIONAL SHAPE DETERMINATION OF SMALL METAL PARTICLES

The three‐dimensional habit of small metal crystallites (> 5 nm in size) can be determined by a combination of selected‐zone dark‐field (SZDF) and weak‐beam dark‐field (WBDF) transmission electron mirosccopy. The information can be obtained from one electron micrograph which is taken in a defocused SZDF condition where all reflection images are clearly separated. The method is based on an evaluation of a) the general intensity of corresponding reflection images, which gives rise to the orientation of the particles with respect to the electron beam, and of b) the weak‐beam thickness fringes which appear in those reflection images that were subject to a relatively large excitation error. The particular advantage over the WBDF method proposed earlier by Yacamán and Ocaña is that no tilting sequence is required. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA