Surfing Silicon Nanofacets for Cold Cathode Electron Emission Sites

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Point sources typically show low threshold electron emission due to field enhancement.
• Silicon tip emitters face challenges with oxidation, limiting emission sites and current.
• Novel approaches are needed to realize efficient silicon-based electron emitters.

Purpose of the Study:

• To report low threshold cold cathode electron emission from silicon nanofacets (Si-NFs).
• To investigate the tunable field emission properties of Si-NFs.
• To identify the primary sites responsible for field emission in Si-NFs.

Main Methods:

• Fabrication of silicon nanofacets (Si-NFs) using low energy ion impacts.
• Characterization of field emission properties, including turn-on field and Fowler-Nordheim tunneling.
• Utilizing local probe surface microscopy and Kelvin probe force microscopy for current mapping.
• Employing first-principle density functional theory (DFT) for work function simulations.

Main Results:

• Achieved low threshold (∼0.67 V μm⁻¹) cold cathode electron emission from Si-NFs.
• Demonstrated tunable field emission in the range of 0.67-4.75 V μm⁻¹.
• Identified nanofacet valleys and sidewalls as major contributors to field emission.
• Observed lowest turn-on field attributed to oxide absence and low work function on specific facets.

Conclusions:

• Si-NFs offer a promising platform for efficient cold cathode electron emission, overcoming silicon oxidation limitations.
• The fabrication method allows for tunable field emission characteristics.
• Understanding emission sites is crucial for designing advanced nanostructured electron emitters.
• The methodology can be applied to other nanostructured materials for electron emission studies.