Morphology-controlled synthesis, growth mechanism and optical properties of ZnO nanonails

High-quality ZnO nanonails with different morphologies were synthesized on silicon substrate through a simple low-temperature thermal evaporation process. The obtained ZnO nanonails exhibit well-defined morphologies, single-crystalline orientations, and clean surface without amorphous contamination. The morphologies of the products can be easily controlled by simply tuning the evaporation temperature of indium powder (TIn). The optical properties of the products were studied by Raman and photoluminescence procedures. The growth of nanonails is based on firstly epitaxial sprouting of small nanorods and then the epitaxial growth of nanonails structures with different microstructures due to different zinc vapor pressures and different deposition sites.