Quantifying stoichiometry of mixed-cation-anion Ⅲ-Ⅴ semiconductor interfaces at atomic resolution

摘要

Employing the focal-series reconstruction technique in high-resolution transmission electron microscopy, we obtained true atomic resolution images of interfacial disorder within cation and anion sublattices across interfaces in an InGaSb/InAs heterostructure. This enabled independent quantitative mapping of changes in the In-Ga and As-Sb contents across interfacial regions ～0.6 nm in width. A comparison of the cation and anion sublattice images revealed that intermixing at the InGaSb-on-InAs interface is confined to the In-Ga sublattice. Also, atomic scale roughness within the As-Sb sublattice of the InAs-on-InGaSb interface was discerned. This approach is general, permitting atomic-scale compositional analysis of heterointerfaces with two species per sublattice.