Low carrier density epitaxial graphene devices on SiC

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Graphene exhibits unique electronic properties, but achieving controlled low carrier densities is crucial for advanced device applications.
• Fabrication processes often introduce surface residues that degrade graphene's intrinsic transport characteristics.
• Understanding and controlling carrier density is key to unlocking graphene's potential in electronics.

Purpose of the Study:

• To report the transport characteristics of graphene devices fabricated with a novel process.
• To investigate graphene with low n- or p-type carrier densities (approximately 10^10 - 10^11 cm^-2).
• To demonstrate the effectiveness of a new fabrication technique in minimizing organic surface residues.

Main Methods:

• Fabrication of graphene devices using a new process designed to minimize organic surface residues.
• Utilizing aqua regia for p-type molecular doping to achieve low carrier densities.
• Characterization of transport properties including Hall resistance measurements.

Main Results:

• Graphene devices with low carrier densities (∼10^10 - 10^11 cm^-2) were successfully fabricated.
• The new fabrication process resulted in minimal organic surface residues.
• Highly developed ν = 2 quantized Hall resistance plateaus were observed at magnetic fields below 4 T.

Conclusions:

• The novel fabrication process enables the production of high-quality graphene with controlled low carrier densities.
• The observed quantized Hall effect indicates the potential of these graphene devices for sensitive electronic applications.
• Minimal surface residues are critical for achieving superior transport properties in graphene devices.