This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
Figure 3443 shows high-resolution HAADF Z-contrast STEM images presenting the interface between Si3N4 matrix (on the top of each image) and the mixtures (at the bottom of each image) of Yb2O3 and Al2O3 (a) and Yb2O3 and SiO2 (b). The Yb atoms, visible here as bright spots due to enhanced electron scattering (giving higher Z-contrast), are located periodically along the interface. The images are oriented along the low-index zone axis  of Si3N4. Note the hexagonal ring structures represent the typical Si3N4 atomic structure  based on phase reconstruction microscopy techniques, even though the individual close atomic positions of Si–N cannot be fully resolved here because the limit of the spatial resolution of the STEM system used.
Figure 3443. High-resolution STEM images showing the atomic interface between a Si3N4 matrix
grain and two different mixtures. Adapted from 
 A. Ziegler, M. K. Cinibulk, C. Kisielowski, and R. O. Ritchie, Atomic-scale observation of the grain-boundary structure of Yb-doped and heat-treated silicon nitride ceramics, Appl. Phys. Lett. 91, 141906 (2007).
 A. Ziegler, J. C. Idrobo, M. K. Cinibulk, C. Kisielowski, N. D. Browning, and R. O. Ritchie, Appl. Phys. Lett. 88, 041919 (2006).