Remote CF₄ Plasma Fluorination of Graphene for Low-Damage Spin-Orbit Engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Defect functionalization is a key strategy for tuning graphene's electronic properties.
• Enhancing spin-orbit coupling (SOC) in graphene is crucial for spintronic applications.
• Controllable fluorination of graphene without significant lattice damage is a persistent challenge.

Purpose of the Study:

• To demonstrate a low-damage fluorination method for monolayer graphene.
• To achieve controllable sp3 C-F functionalization while minimizing vacancy formation.
• To investigate the impact of fluorination on graphene's spin transport properties and SOC.

Main Methods:

• Utilized a remote CF4 plasma process for low-damage fluorination.
• Employed Raman spectroscopy with defect-activation analysis and annealing-reversibility tests.
• Conducted nonlocal transport measurements to assess spin diffusion and relaxation length.

Main Results:

• Identified a processing window for reversible sp3 C-F functionalization with minimal lattice damage.
• Observed an increase in nonlocal resistance in fluorinated graphene, indicating enhanced spin diffusion.
• Determined a spin relaxation length of approximately 0.4 μm and estimated an effective SOC energy scale of 4-9 meV.

Conclusions:

• The developed remote CF4 plasma process enables tunable, low-damage fluorination of graphene.
• This method effectively enhances spin-orbit coupling in graphene while preserving lattice integrity.
• The findings offer a viable route for fabricating graphene-based spintronic devices with improved performance.