Field Assisted Reactive Gas Etching of Multiple Tips Observed using FIM

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Fabricating single atom tips (SATs) is crucial for advanced microscopy and surface science applications.
• Current methods for producing multiple tungsten (W) SATs can be complex and costly.
• Developing efficient, scalable fabrication techniques for W SATs is an ongoing challenge.

Purpose of the Study:

• To report a simple and cost-effective method for fabricating multiple tungsten single atom tips (SATs).
• To demonstrate the simultaneous fabrication of multiple tips from both polycrystalline and single crystalline tungsten wires.
• To facilitate mass fabrication and characterization of tungsten tips.

Main Methods:

• Electrochemical etching of multiple tungsten tips in NaOH solution.
• Controlled field-assisted reactive gas etching in vacuum using nitrogen and helium.
• Application of common high voltage for simultaneous apex shaping of nanotips.

Main Results:

• Successful fabrication of single atom tips (SATs) from W(111) and W(110) crystallographic orientations.
• Achievement of trimer tips from W(111), indicating control over tip morphology.
• Demonstration of simultaneous shaping of multiple tips towards single-atom apexes.

Conclusions:

• The developed method offers a simplified process for etching multiple tungsten tips.
• This technique facilitates the mass fabrication and characterization of numerous tungsten tips.
• The findings represent a significant step towards scalable production of W SATs for scientific applications.