Growth behavior of ZnO nanowires on Au-seeded SiO₂-GaN co-substrate by vapor transport and deposition

Au-seeded amorphous SiO₂ layer with crystalline GaN dot windows was fabricated on c-plane sapphire wafer. In order to compare the growth of ZnO nanostructures on amorphous SiO₂ with that on crystalline GaN directly, the Au-seeded SiO₂-GaN co-substrates were used for the growth of ZnO nanowires by the vapor transport and deposition (VTD) technique. As-prepared ZnO nanowires were characterized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results show that there is an Au particle on the grown ZnO nanowire and the formation of ZnO nanowire on crystalline GaN is easier than that on amorphous SiO₂. The experimental results were explained by the change of Zn contents in an Au-Zn droplet with the co-substrate positions during VTD process and ZnO epitaxial growth.