Enhanced field emission from injector-like ZnO nanostructures with minimized screening effect

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Zinc oxide (ZnO) nanostructures are promising for electronic applications.
• Field emission properties are crucial for devices like field emission displays and X-ray sources.
• Controlling nanostructure morphology and density influences their electronic behavior.

Purpose of the Study:

• To synthesize injector-like ZnO nanostructures on a silicon substrate.
• To investigate the effect of areal density on the field emission properties of ZnO nanostructures.
• To determine optimal conditions for low turn-on field and high current density.

Main Methods:

• Vapour phase transport method used for ZnO nanostructure synthesis.
• Temperature control employed to vary areal densities of nanostructures.
• Field emission measurements conducted to characterize performance.

Main Results:

• Field emission properties strongly depend on the areal density of ZnO nanostructures due to screening effects.
• The lowest field emission turn-on field of 1.85 V µm⁻¹ was achieved at a current density of 10 µA cm⁻².
• Optimal sample parameters: 850 nm needle length and 1 × 10⁸ cm⁻² areal density.
• A current density of 1 mA cm⁻² was reached at an applied field of 4.7 V µm⁻¹.

Conclusions:

• Areal density is a critical factor in optimizing field emission from ZnO nanostructures.
• The synthesized ZnO nanostructures demonstrate excellent field emission characteristics.
• These findings suggest potential for ZnO nanostructures in advanced electronic applications.