Fragmented graphene synthesized on a dielectric substrate for THz applications

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Graphene synthesis is crucial for advanced electronic and photonic applications.
• Controlling graphene quality and structure is essential for optimizing its properties.
• Chemical vapor deposition (CVD) is a common method for graphene fabrication.

Purpose of the Study:

• To develop a scalable method for synthesizing fragmented multi-layered graphene films.
• To investigate the influence of synthesis parameters on graphene integrity and quality.
• To characterize the electrical properties of the synthesized graphene for terahertz (THz) applications.

Main Methods:

• Direct synthesis of graphene via chemical vapor deposition (CVD) on dielectric substrates with a copper catalyst.
• Utilizing atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) for surface characterization.
• Employing THz time domain spectroscopy (THz-TDS) to measure AC conductivity.

Main Results:

• Graphene film integrity, quality, and disorder are influenced by copper film thickness, process temperature, and growth time.
• AFM and KPFM revealed nano-agglomerates and charge puddles, indicating a multilayered structure.
• THz-TDS measurements showed AC conductivity of graphene flakes and homogenized films around 1200 S cm⁻¹ and 1000 S cm⁻¹, respectively.

Conclusions:

• A scalable fabrication approach for graphene structures composed of flakes was demonstrated.
• The synthesized graphene possesses effective conductivity suitable for various THz applications.
• The study provides insights into controlling graphene properties through CVD parameters.