N. Tanaka et al., ULTIMATE OBSERVATION OF TUNGSTEN ATOMS AND CLUSTERS ADSORBED ON SINGLE-CRYSTALLINE MGO FILMS, Microscopy research and technique, 40(4), 1998, pp. 265-276
Tungsten single atoms and clusters composed of four and five atoms dep
osited on MgO (001) thin films were observed by high-resolution transm
ission electron microscopy at R.T. The observation was realized by opt
imizing the thickness of the MgO films and by using special imaging te
chniques such as an off-Bragg HREM method. The multislice simulation f
or the interpretation of the image contrast showed a possibility of di
scrimination of the atomic configuration of clusters, such as ''b.c.c.
,'' ''on-top,'' or ''f.c.c.'' type clusters, from details of the image
-contrast. The image intensity at the center of the clusters with the
b.c.c. configuration was evidently smaller than that of the clusters w
ith the f.c.c. configuration. The reason for the difference was clarif
ied through the multislice image simulation, suggesting that the latti
ce mismatch between the clusters and the MgO lattice was a key factor
in determining the intensity of the center of the clusters. (C) 1988 W
iley-Liss, Inc.