Nucleation and growth of ZnO nanorods on the ZnO-coated seed surface by solution chemical method

ZnO nanorods on ZnO-coated seed surfaces were fabricated by solution chemical method using supersaturated (ZnNO3)2/NaOH at 70 °C. The seed surfaces were coated on glass substrates by sol–gel processing, and their texture was dominated by heating temperatures, cooling styles and layer thickness per dipping. The effects of the seed surface on the morphology of the resultant nanorods were primarily discussed. The orientation and morphology of both the seed surface and successive nanorods were analyzed by using XRD and SEM. It is proved that when the seed size increases from 15 to 50 nm with temperature increasing, the average diameter of the resultant nanorods increase from 25 to 50 nm, with a length of 800 nm after growing for 1.5 h. The seed surface prepared by heating at 300–400 °C, fast cooling or drawing at lower speed has better orientation and few surface defects, which leads to higher density of nuclei on the seed surface and thus to the optimal preferred crystal growth of ZnO rods standing perpendicular onto substrates.