Zinc oxide nanorod growth on gold islands prepared by microsphere lithography on silicon and quartz

Gold islands, vapor deposited on silicon and quartz by microsphere lithography patterning, are used to nucleate arrays of ZnO nanorods. ZnO is grown on similar to 0.32 mu m(2) Au islands by carbothermal reduction in a tube furnace. Scanning electron microscopy (SEM) and energy dispersive atomic X-ray spectroscopy (EDS) confirm that the gold effectively controls the sites of nucleation of ZnO. Atomic force microscopy (AFM) shows that similar to 30 nm diameter nanorods grow horizontally, along the surface. Alloy droplets that are characteristic of the vapor-liquid-solid (VLS) mechanism are observed at the tips of the nanorods. The spatial growth direction of VLS catalyzed ZnO nanorods is along the substrate when they nucleate from gold islands on silicon and quartz. The energy of adhesion of the VLS droplet to the surface can account for the horizontal growth.