From nanoparticle chains to nanorods: control of ZnO nanostructures by laser ablation

Pb-doped ZnO nanostructures were prepared using millisecond pulse-width laser ablation. Nanoparticle chains formed when the laser ablation was performed in air or on a pure Zn target, and when Ar flow was introduced it could be used to mediate the nucleation and growth of crystalline nanorods from a composite Zn/Pb target. Based on the results of control experiments, a mechanism was proposed to explain the formation of the observed nanostructures. Namely, the millisecond laser pulse can generate metal nanodroplets in contrast to a plasma or vapor plume, which then react with the controlled environmental gas to give rise to different nanostructures. The final morphology is dependent on the target composition and oxygen content of the ambient atmosphere during ablation.