Modeling of epitaxial graphene functionalization.

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Epitaxial graphene on silicon carbide (SiC) is a promising material for electronics.
• Understanding adatom functionalization is crucial for tuning graphene's electronic properties.

Purpose of the Study:

• To model the functionalization of epitaxial graphene on SiC using various adatoms.
• To investigate the impact of adatom size and concentration on graphene's structure and electronic properties.

Main Methods:

• Density Functional Theory (DFT) modeling was employed.
• Simulations considered functionalization by hydrogen, fluorine, methyl, and phenyl groups.

Main Results:

• Hydrogen and fluorine adatoms tend to form clusters at high concentrations.
• Fluorine adatom clustering induces significant graphene lattice distortion, creating midgap states.
• Larger methyl and phenyl groups lead to uniform graphene coverage due to steric hindrance, opening an energy gap.

Conclusions:

• Adatom species significantly influence the functionalization outcome of epitaxial graphene on SiC.
• Controlled functionalization can be achieved by selecting appropriate adatom sizes, enabling tuning of graphene's electronic band structure.