Synthesis and cathode luminescence properties of ZnO multipod nanoneedles

Zinc oxide (ZnO) multipod nanoneedles over a large area have been synthesized on silicon substrate by thermally oxidizing zinc foil at 650 °C. These nanoneedles have sharp tails with diameter down to less than 100 nm, with length of 10 μm, growing from the surface of the silicon substrate and legs connected at a common base. X-ray diffraction (XRD) confirmed the sample as pure ZnO nanostructures with growth direction of [002]. The cathode luminescence behaviors at different regions of an individual nanoneedle of these multipod ZnO nanostructures were characterized. It is shown the whole nanostructures are luminescent, while the tips have relative higher visible emission than the bottom. The cathode luminescence mechanisms were also discussed.