A novel method for synthesis of well-aligned hexagonal cone-shaped ZnO nanostructures in field emission applications

• A relatively fast, easy and inexpensive technique was used for synthesis of well-aligned hexagonal cone-shaped ZnO nanostructures.
• The field emission and optical properties were studied.
• The PL spectra show blue shifts in near-band-edge emission and green region peaks by increasing process temperature.
• We report the lowest turn-on electric field, largest field-enhancement factor, and good stability for the cone-like ZnO nanorods fabricated by the electric field-assisted chemical bath depositionmethod.

Well-aligned and high-density ZnO nanocone arrays were prepared on Si substrates using an electric field-assisted chemical bath deposition (FECBD) method. The photoluminescence (PL) spectra of ZnO nanostructures indicate that near-band-edge (NBE) emission shifted slightly toward lower wavelengths with the increase in procedure temperature, and the intensity increased with improved ZnO crystallization. The cone-shaped ZnO nanorods had the lowest turn-on electric field, largest field-enhancement factor, and good stability, which were attributed to the small emitter radius at the tip, uniform density distribution, and high aspect ratio. These results indicate that the cone-shaped ZnO nanostructures fabricated by FECBD are promising for application as field emission (FE) electron sources.