A theoretical model for metal-graphene contact resistance using a DFT-NEGF method

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Contact resistance (R(c)) is critical for graphene device performance.
• Existing models fail to account for Fermi velocity differences at metal-graphene interfaces.

Purpose of the Study:

• To develop a theoretical model for estimating R(c) in graphene-metal contacts.
• To incorporate the Fermi velocity mismatch between contacted and uncontacted graphene.

Main Methods:

• Density-functional theory (DFT) calculations.
• Non-equilibrium Green's function (NEGF) methods.
• Theoretical modeling of metal-graphene interfaces.

Main Results:

• A novel theoretical model for R(c) was developed.
• The model provides a clear physical understanding of contact mechanisms.
• Predicted R(c) values align well with experimental data (e.g., 210 Ω μm for double-sided Pd contacts).

Conclusions:

• The new model accurately predicts graphene contact resistance.
• This work advances the understanding and design of graphene-based electronic devices.
• Accurate R(c) estimation is vital for optimizing graphene device performance.