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 with- out 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 elec- tron microscope (SEM), which described the direct observation nucleation and growth process. Meanwhile, room tempera- ture 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.