Synthetics of ZnO nanowires on GaN micro-pyramids by gold catalyst

GaN micro-pyramids were fabricated on n-type CaN buffer layer/c-plane sapphire wafer. In order to understand the growing ZnO on GaN {1–1 0 1} facets, ZnO nanostructures on GaN micro-pyramids with and without Au catalyst were synthesized by chemical vapor deposition (CVD). As-prepared ZnO nanostructures were characterized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). ZnO nano-sheets on the micro-pyramids without Au catalyst have a terrace-like structure, which is explained by vapor–solid mechanism. ZnO nanowires with a gold particle on the top grow on micro-pyramids with Au catalyst, which is explained by vapor–liquid–solid mechanism. Nanowire bridges crosslinking two adjacent micro-pyramids are frequently observed, which demonstrates the capability to develop self-organizing electrical interconnects and nanoscale devices. The diameters of the resulting ZnO nanowires are in the range of 40–100 nm with typical length about 10 μm.

► Growth of ZnO nanostructures on GaN {1–1 0 1} facets of micro-pyramids.
► ZnO nano-sheets grown on the micro-pyramids without Au catalyst.
► ZnO nanowires with Au particles on top growing on micro-pyramids with Au catalyst.
► Nanowire bridges crosslinking two adjacent micro-pyramids.