Effect of nitrogen gas in the agglomeration and photoluminescence of Zn-ZnO nanowires after high-temperature annealing

Abstract

The effect of anti-agglomeration and enhanced photoluminescence after high-temperature annealing of Zn-ZnO nanowires in nitrogen atmosphere is reported. The Zn-ZnO nanowires were deposited by the hot filament chemical vapor deposition technique and subsequently annealed at 1100$^{\circ}$C in oxygen or nitrogen atmospheres. It was found that under both annealing atmospheres, the structure of the nanowires was completely oxidized. Morphological studies suggest that annealing under oxygen-rich atmosphere, grain growth occurs, resulting in a continuous surface with a micrograin-shaped structure. However, it seems that nitrogen-rich annealing partially prevents complete agglomeration and longitudinal structures composed by nanometric grains were observed. Although photoluminescence properties of the annealed nanowires are improved in both annealing atmospheres, it was observed that the PL spectrum of nanowires annealed in nitrogen showed a stronger UV emission than that of the oxygen annealed nanowires.