Rapid Formation and Evolution of Anodized-Zn Nanostructures in NaHCO3Solution

Densely packed nanowires were fabricated by anodizing zinc foil in slightly basic sodium bicarbonate solution. The formation of different nanostructures was observed as a result from varying the reaction parameters such as voltage, electrolyte concentration and time. An in-depth analysis of these formation stages enables a growth mechanism to be proposed. The evolution of anodized-Zn nanostructures could be categorized into four stages, i.e. pitting, growth of nanofibers in pit, formation of nanoflowers and transformation to nanowires. The fabricated nanowires being amorphous in nature, whilst the FTIR measurement revealed the chemical bonds within the nanowires attributed to zinc hydroxy carbonate/hydrozincite. Hydrozincite nanowires were converted into hexagonal wurtzite ZnO after heat-treatment at 250°C for 1 h as verified by XRD measurement. The overall nanowires form was preserved after annealing but it displayed a granular surface. This surface texture will aid researchers to design/optimize the total expose surface area and yield device grade performances.