Sea-urchin-like ZnO nanostructures on Si by oxidation of Zn metal powders: Structural and optical properties

High-density sea-urchin-like ZnO nanostructures were grown on Si(100) substrates by the oxidation of metallic Zn powders at a low growth temperature without the use of any catalyst or additives. The morphological studies indicated that the grown structures are uniformly dispersed on the substrate and exhibited a sea-urchin-like shape consisting of several thousands of nanorods in one array, each ZnO nanorod of these structures having the diameter of 20-50 nm with the length of 2-4 μm. The high-resolution transmission electron microscopy and selected area electron diffraction patterns showed that the prepared sea-urchin-like ZnO nanostructures were single crystalline with wurtzite hexagonal structure and preferably grown along the [0001] direction. Room temperature Raman scattering and photoluminescence studies found that the as-grown nanostructures have good crystal quality with the hexagonal wurtzite phase.