Vertically well-aligned ZnO nanowires generated with self-assembling polymers

Vertically well-aligned ZnO nanowires were prepared on the (1 1 1) plane of silicon substrates by using polyvinyl alcohol (PVA) as self-assembling complex polymer. A polymer solution containing ligands Zn 2+ via complexing the homogenous polar radicals hydroxy groups (–OH) in polymers with Zn 2+ ions in semiconductor metal salts was distributed evenly on Si substrates by coating. Then, Zn 2+ transforms into ZnO quantum nanospots by chemical transformation and thermal hydrolysis. All the polymers were removed after chemical oxdization and only the carbonized grid backbones remained that confine the ZnO nanowire's diameter and enhance the absorption and diffusion of ZnO at the tips of nanowires during growth. The ZnO nanowires have been characterized by FE-SEM and XRD. The results indicated that the nanowires are hexagonal ZnO and the diameter of ZnO semiconductor nanowires varies from 20 to 80 nm and the length up to about 1 μm. A polymer localized ZnO growth model is proposed, which well explains the growth behavior of ZnO nanowires.