The effect of growth parameters on the aspect ratio and number density of CuO nanorods

We have studied how different growth conditions, namely, oxygen flow rate, annealing temperature and annealing time affect the diameter, aspect ratio and number density of CuO nanorods using scanning and transmission electron microscopy. CuO nanorods are synthesized by thermal annealing of thin copper foil. It is observed that while the diameter and number density of nanorods depend critically on the oxygen flow rate and annealing temperature, the aspect ratio and dispersion in diameter of nanorods can mostly be improved by thermal annealing for extended time periods. The growth mechanism of the nanorods is inferred from the evolution of observed microstructural changes. It is proposed that the growth of nanorods takes place from triangular shaped pyramids due to the relaxation of stress accumulated in oxide film during the process of oxidation and annealing.