Epitaxial growth of ZnO nanowall networks on GaN/sapphire substrates

Heteroepitaxy of vertically well-aligned ZnO nanowall networks with a honeycomblike pattern on GaNc- Al2 O3 substrates by the help of a Au catalyst was realized. The ZnO nanowall networks with wall thicknesses of 80-140 nm and an average height of about 2 μm were grown on a self-formed ZnO thin film during the growth on the GaNc- Al2 O3 substrates. It was found that both single-crystalline ZnO nanowalls and catalytic Au have an epitaxial relation to the GaN thin film in synchrotron x-ray scattering experiments. Hydrogen-sensing properties of the ZnO nanowall networks have also been investigated.