Facet-selective epitaxial growth of δ-Bi₂O₃ on ZnO nanowires

Integration of ZnO nanowires with Bi₂O₃ coating layers can modify their physicochemical properties and efficiently improve the performance of the resulting nanostructured composites for specific applications. The interfacial structures often control the properties of such nanocomposite systems. We report a novel approach to achieving selective epitaxial growth of δ-Bi₂O₃ layers onto the {11-20} nanoscale facets of ZnO nanowires. By detailed atomic scale characterization of the surfaces and interfaces of the Bi₂O₃/ZnO nanocomposites we proposed that growth of the δ-Bi₂O₃ species on ZnO {11-20} surfaces follows the Stranski-Krastanov mechanism with an epitaxial relationship of ZnO [10-10] (11-20)∥δ-Bi₂O₃ [001] (100). An atomic model is proposed to explain the epitaxial relationship, the interfacial atomic structure, and the facet-selective growth.