UC Santa Barbara

High-angle annular dark-field (HAADF) imaging in scanning transmission electron microscopy was used to determine the atomic structure of interfaces between epitaxial ErAs layers with the cubic rock salt structure and In0.53Ga0.47As and GaAs, respectively. All layers were grown by molecular beam epitaxy. We show that the interfacial atomic arrangement corresponds to the so-called chain model, in which the zinc blende semiconductor is terminated with a Ga layer. Image analysis was used to quantify the expansion between the first ErAs plane and the terminating Ga plane. In the HAADF images, a high intensity transfer from the heavy Er columns into the background was observed in the ErAs layer, whereas the background in In0.53Ga0.47As was of much lower intensity.