Mapping of local electrical properties in epitaxial graphene using electrostatic force microscopy

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Epitaxial graphene on silicon carbide (SiC) is a promising material for electronics.
• Characterizing graphene layers, especially on SiC, is challenging due to surface adsorbates.
• Local electrical properties are crucial for understanding graphene device performance.

Purpose of the Study:

• To present local electrical characterization of epitaxial graphene on 4H-SiC(0001) using Electrostatic Force Microscopy (EFM).
• To demonstrate EFM's capability in identifying graphene layers despite topographical hindrances from adsorbates.
• To introduce and validate a novel EFM spectroscopy technique for distinguishing graphene domains.

Main Methods:

• Utilized Electrostatic Force Microscopy (EFM) for imaging.
• Performed characterization under ambient conditions and at elevated temperatures.
• Developed and applied a new EFM spectroscopy method measuring EFM phase versus DC bias.

Main Results:

• EFM effectively identified graphene with varying layer numbers on 4H-SiC(0001).
• Adsorbates on the surface did not prevent successful graphene layer identification via EFM.
• The novel EFM spectroscopy rigorously distinguished different graphene domains.
• Optimized EFM imaging parameters were facilitated by the new technique.

Conclusions:

• EFM is a powerful tool for local electrical characterization of epitaxial graphene on SiC.
• The developed EFM spectroscopy offers a robust method for differentiating graphene domains.
• This work facilitates improved quality control and device optimization for graphene-based electronics.