urchin-like structures made of ultra-thin zinc oxide nanowires †

We report the synthesis of ultra-thin, monocrystalline, highly luminescent ZnO nanowires (NWs) on polystyrene (PS) beads as templates. The synthesis of these NWs on PS beads was conducted by the chemical bath deposition technique in the absence of any catalysts or additives. They have an average diameter of 15 nm (depending on the concentration of the solution) and an average length of 500 nm. Structural characterization reveals that these NWs are monocrystalline, with a hexagonal phase and grow along the [0001] direction. Photoluminescence measurements of these unannealed, ultra-thin NWs exhibit a strong ultra-violet emission at room temperature with an internal quantum efficiency of 23%. We show that the concentration of the aqueous solution plays a key role in controlling the size of the NWs.