ZnO–Si side-to-side biaxial nanowire heterostructures with improved luminescence

Using as-obtained ZnS–Si biaxial nanowires as templates, which were prepared via a thermal evaporation of a mixed powder of SiO and ZnS under controlled temperature, ZnO–Si biaxial nanowire heterostructures were achieved by a simple post-oxidation process. Each ZnO–Si composite nanowire has a uniform diameter along its whole length; the typical diameter of the nanowires ranges from 100 to 500 nm, and the diameters of Si- and ZnO-side sub-nanowires within a nanowire heterostructure are ∼50–250 nm. Significant enhancement of green luminescence compared to the ZnO nanowires has been observed from these ZnO–Si biaxial nanowire heterostructures, which may find the applications in short wavelength photoelectric devices, fluorescence labels, and biological detectors. The present template-assisted method demonstrated here could be a general approach of fabricating nanowire heterostructures made of Si-based materials.