Interface atomic structure of epitaxial ErAs layers on (001) In_(0.53)Ga_(0.47)As and GaAs

摘要

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 In_(0.53)Ga_(0.47)As 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 In_(0.53)Ga_(0.47)As was of much lower intensity.