Superior field emission properties of ZnO nanocones synthesized by pulsed laser deposition

C-axis oriented ZnO nanocones have been synthesized by pulsed laser deposition (PLD) on a Si substrate. The nanocones are 100–200 nm wide at the base and <20 nm at the tip, and are distributed fairly uniformly on the substrate at a density of approximately 100 μm−2. The field emission measurement of ZnO nanocones reveals that they have a large field enhancement factor of 2216 and low turn-on field of 2.57 V/μm; the former is greater than that of ZnO nanorods with a comparable area density, suggesting that the tapered cone-like morphology is more efficient for field emission displays.