Effect of seed layer on the growth of ZnO nanorods

To investigate the effect of seed layer on the growth of ZnO nanorods during hydrothermal synthesis, different types of sputter-deposited ZnO films were used. The changes in growth rate, diameter, density, and surface area of highly oriented ZnO nanorods on each seed layer were examined. The growth rate of ZnO nanorods has a strong relationship with the intensity of (0001) orientation. The density of nanorods per unit area is larger if the diameter of the nanorods is smaller. The total surface area of ZnO nanorods is determined by the growth rate and density per unit area. It was found that the morphology of the ZnO nanorods is strongly influenced by the thickness of the seed layer and the corresponding crystal size. A thinner ZnO seed layer provides a higher surface area of ZnO nanorods because of the smaller crystal size of the seed layer. The orientation of the ZnO seed layer significantly affects the crystallinity of the nanorods.