Two-dimensional dendritic ZnO nanowires from oxidation of Zn microcrystals

Spontaneous formation of ZnO dendritic nanowires has been achieved on the faceted surfaces of polyhedral Zn microcrystals by oxidizing the latter at 600°C. Electron microscopy investigations reveal that all the dendritic branches are elongated in 〈11-20〉 directions within the ±(0001) primary planes, forming two-dimensional web-like structure. Homoepitaxial interconnections are observed at the branch-to-arm and branch-to-branch regions, and the whole dendrites are wurtzite single crystals. The growth process of the dendritic nanowires is discussed, which is proposed to be a combination of "self-catalytic liquid-solid" and vapor-solid process.