Nitridation of diamond(111) surface by density functional theory

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Diamond(111) surfaces exhibit varied terminations and reconstructions.
• Nitrogen plasma interactions with diamond are crucial for material functionalization.

Purpose of the Study:

• To investigate nitrogen species adsorption and thermal evolution on diamond(111) using density functional theory.
• To elucidate the role of surface structure in nitrogen incorporation and desorption.

Main Methods:

• Density functional theory (DFT) calculations.
• Modeling of bare and hydrogenated diamond(111) surfaces (C(111)-2 × 1, graphite-like C(111), C(111)-2 × 1-H, C(111)-1 × 1-H).
• Simulation of microwave N2 plasma impact.

Main Results:

• N2(ad) is the primary species on bare diamond domains, desorbing via concerted C-N bond breaking.
• (NH)2(ad) forms on hydrogenated diamond via N2 insertion.
• Desorption of (NH)2(ad) differs: sequential on C(111)-2 × 1-H, concerted on C(111)-1 × 1-H.

Conclusions:

• Surface terminations and reconstructions on diamond(111) explain the diversity of observed nitrogen species.
• DFT provides insights into nitrogen adsorption, bonding, vibration, and desorption mechanisms.
• Understanding these surface dynamics is key for controlling nitrogen incorporation in diamond materials.