Structural analysis of ZnO nanowalls grown by vapor-liquid-solid method using Ni catalyst

Using a Ni catalyst instead of Au, we synthesized a ZnO nanowall structure on a-plane (11-20) sapphire substrates by the vapor-liquid-solid technique under optimized conditions. We studied its structural properties and chemical composition using nanobeam diffraction with transmission electron microscopy (TEM) and scanning TEM-energy-dispersive spectroscopy. ZnO nanowalls about 100 nm thick with an average height of 1 um were grown. The heated Ni formed a network on the sapphire substrate and was subsequently oxidized; the network supported nanowall formation. Interlayers and ZnO nanowalls grew by diffusion of evaporated Zn. TEM revealed that ZnO nanowall growth was associated with the oxidized Ni network and the interlayers.