Local voltage drop in a single functionalized graphene sheet characterized by Kelvin probe force microscopy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene's unique electronic properties make it promising for next-generation electronics.
• Understanding local voltage drops and contact resistance is crucial for device performance.

Purpose of the Study:

• To investigate the local voltage drop in functionalized graphene sheets.
• To determine the intrinsic conductivity and sheet resistance of graphene.
• To quantify the contact resistivity between graphene and metal electrodes.

Main Methods:

• Utilized Kelvin probe force microscopy (KPFM) for noninvasive local voltage measurements.
• Applied external bias conditions to functionalized graphene sheets of sub-micrometer size.
• Analyzed current-voltage (I-V) characteristics.

Main Results:

• Measured ohmic current-voltage characteristics.
• Determined an intrinsic conductivity of approximately 3.7 × 10^5 S/m.
• Calculated a sheet resistance of 2.7 kΩ/sq under ambient conditions.
• Found contact resistivity between functionalized graphene and metal electrodes to be less than 6.3 × 10^-7 Ωcm^2.

Conclusions:

• Functionalized graphene produced via thermal reduction of graphite oxide exhibits favorable electrical properties.
• Low contact resistivity suggests efficient charge transfer, beneficial for electronic device integration.
• The findings support the use of this graphene material in various electronic applications.