Synthesis of tetrapod-shaped ZnO nanowires by directive oxidation of Al-Zn mixture

Abstract

Tetrapod-shaped ZnO nanowires were synthesized by the directive oxidation process of Al-Zn mixtures containing Mg. Mg played a crucial role in the formation of the ZnO nanowires. X-ray diffraction data and SEM images of the nanowires revealed that the ZnO nanowires were single crystalline with wurtzite structure of hexagonal phase. With increasing Mg concentration in Al-Zn mixture from 2 mass% to 8 mass%, the tip morphology of the nanowires changed from spherical shape to needle-like shape, and went back to spherical shape. The quantity of the nanowires first increased and then decreased with Mg concentration. From Energy dispersive X-ray spectrum and SEM image taken for the tip of the ZnO nanowire, it is supposed that the growth of the nanowires proceeded in vapor-solid mechanism. The green emission centered at 510 nm was observed at room temperature, which resulted from high density of oxygen vacancies in the nanowires.