First-Principles Study of Adsorption of Pb Atoms on 3C-SiC

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Silicon carbide (SiC) is a crucial material in various industrial applications.
• Understanding its surface interactions is vital for predicting material degradation.
• Lead adsorption is a potential factor influencing SiC's electronic and atomic structure.

Purpose of the Study:

• To investigate the atomic and electronic structure changes in 3C-SiC (β-SiC) upon lead adsorption.
• To analyze the primary mechanisms driving the corrosion of silicon carbide.
• To quantify the impact of lead coverage on SiC surface properties.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Analysis of bond lengths, bond energies, Bader charges, and charge density differences.
• Simulations were performed on three representative SiC surfaces: (100), (110), and (111).

Main Results:

• Chemisorption of lead onto SiC surfaces was confirmed.
• The strongest lead-silicon carbide interaction was observed on the (111) surface, involving three dangling bonds.
• Adsorption energy increased with lead coverage, particularly near surface saturation.
• Surface atomic bonds weakened due to lead interactions, promoting dissolution corrosion.

Conclusions:

• Lead adsorption significantly alters the atomic and electronic structure of 3C-SiC.
• The (111) surface exhibits the highest susceptibility to lead-induced corrosion.
• Weakening of surface bonds by lead is a key mechanism in silicon carbide dissolution corrosion.