Low-temperature synthesis of novel ZnO nanowire microspheres on silicon substrates

Microspheres covered with ZnO nanowires were fabricated by oxidative evaporation of pure zinc powder without catalyst at 450°C. X-ray diffraction (XRD) demonstrates that the as-obtained sample can be indexed to high crystallinity with wurtzite structure. The structural features associated with different growth stages were monitored using scanning electron microscope (SEM), which described the direct observation nucleation and growth process. Meanwhile, room temperature photoluminescence (PL) spectrum showed a UV emission at ∼388 nm and a broad green emission at ∼505 nm. The ZnO nanowires with the self-catalyzed growth mechanism were discussed in detail.