Epitaxial relationships of ZnO nanostructures grown by Au-assisted pulsed laser deposition on c- and a-plane sapphire

► X-ray diffraction reveals epitaxial relationships of ZnO nanostructures on sapphire. ► Tilted nanowires on c-sapphire show a two-fold degeneracy of the in-plane alignment. ► The full epitaxial relationships of ZnO nanosheets on a-sapphire are reported. ► The observed configurations are modeled and explained by reduced lattice mismatch. ► Reduced lattice mismatch favors tilted over vertical nanowire growth on c-sapphire.