Unexpected Epitaxial Growth of a Few WS2 Layers on {11̅00} Facets of ZnO Nanowires

Core–shell nanowires are an interesting and perspective class of radially heterostructured nanomaterials where epitaxial growth of the shell can be realized even at noticeable core–shell lattice mismatch. In this study epitaxial hexagonally shaped shell consisting of WS2 nanolayers was grown on {1100} facets of prismatic wurtzite-structured [0001]-oriented ZnO nanowires for the first time. A synthesis was performed by annealing in a sulfur atmosphere of ZnO/WO3 core–shell structures, produced by reactive dc magnetron sputtering of an amorphous a-WO3 layer on top of ZnO nanowire array. The morphology and phase composition of synthesized ZnO/WS2 core–shell nanowires were confirmed by scanning and transmission electron microscopy (SEM and TEM), micro-Raman, and photoluminescence spectroscopy. Epitaxial growth of WS2(0001) layer(s) on {1100} facets of ZnO nanowire is unexpected due to incompatibility of their symmetry and structure parameters. To relax the interfacial incoherence, we propose a model of ZnO/...