Journal of Crystal Growth, Vol.277, No.1-4, 471-478, 2005
Catalyst-free synthesis of ZnO nanowires on Si by oxidation of Zn powders
ZnO natioNvires were grown on Si (100) substrates by oxidation of metallic Zn powder at 600 degrees C. Sea-urchin-like nanostructures, consisting of straight nanowires of ZnO with blunt faceted ends with a sudden reduction in diameter projecting out, were observed, having diameters of 30-60 nm and lengths of 2-4 mu m. TEM analysis and SAED patterns showed that the as-grown nanostructures are highly crystalline in nature and preferably grown along the  direction, which is consistent with XRD analysis. Room-temperature photoluminescence (PL) measurements showed a reduced near band-edge emission in the UV region at 380 nm, while a strong deep level emission was observed in the visible region at 500-530 nm. A model for vapor-solid (VS) growth mechanism of ZnO nanowires was presented. (c) 2005 Elsevier B.V. All rights reserved.