Vertical nanodiamond dominated sheets possessing both high capacitance and high n-type Hall mobility.

Area of Science:

• Materials Science
• Nanotechnology
• Plasma Physics

Background:

• Vertical graphene (VG) sheets are challenging to prepare in a nanodiamond-dominated form.
• Developing efficient methods for synthesizing vertical nanodiamonds (VNDs) is crucial for advanced material applications.

Purpose of the Study:

• To describe a novel method for preparing vertical nanodiamond (VND) dominated sheets.
• To investigate the effect of varying oxygen percentages during plasma treatment on the transformation of VGs to VNDs.

Main Methods:

• Phase transformation of tantalum-loaded vertical graphene (VG) sheets.
• Argon/oxygen plasma treatment with controlled oxygen concentrations (5%, 10%, 20%).
• Characterization of material properties including capacitance and Hall mobility.

Main Results:

• At 5% oxygen, VG height decreased, showing high capacitance and low Hall mobility.
• At 10% oxygen, VGs transformed into nanocrystalline diamond (NCD) grains with increased trans-polyacetylene (TPA) in grain boundaries, achieving 1452 μF cm⁻² capacitance and 846 cm² V⁻¹s⁻¹ n-type Hall mobility.
• At 20% oxygen, NCD grains grew, TPA content decreased, capacitance dropped, but Hall mobility remained high, indicating a synergistic effect.

Conclusions:

• The study successfully demonstrates the preparation of VNDs from VGs via plasma treatment.
• Optimal oxygen percentage (10%) leads to a synergistic effect between NCDs and TPA, enhancing performance.
• The synthesized VNDs show significant potential for energy storage, sensors, and high-frequency/power electronics.