Acetylene adsorption on silicon (100)-(4 × 2) revisited

• Published in: Surface science Vol. 605; no. 15; pp. 1341 - 1346
• Main Authors: Czekala, Piotr T., Lin, Haiping, Hofer, Werner A., Gulans, Andris
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.08.2011; Elsevier
• Subjects: Acetylene; Adsorption; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Contours; Cross-disciplinary physics: materials science; rheology; DFT; Exact sciences and technology; Physics; Scanning tunneling microscopy; Semiconductor; Silicon; Silicone; Simulation; STM; Surface chemistry; Van der Waals forces; 100; Semiconductor; DFT; STM; Silicone; Acetylene; Scanning tunneling microscopy; Semiconductor materials; Density functional method; Silicon
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2011.03.024

The aim of this work is to revisit the problem of acetylene adsorption on silicon (100). Extending previous theoretical work and including van der Waals forces explicitly in the simulations we remove existing ambiguities about the adsorption sites. The simulated adsorption energies and scanning tunneling microscopy contours are in good agreement with experimental data, they support the interpretation of a two-dimer feature at the surface as resulting from the adsorption of two individual molecules. It is also found that the simulated apparent heights agree with experimental values, if the actual bandgap of silicon is taken into account. ► Revisit of acetylene adsorption on silicon by theoretical methods including van der Waals interactions. ► Adsorption configuration found to be di-sigma bonded in all cases. ► Two-dimer footprint in scanning tunneling microscopy (STM) images unambiguously found to be due to two adjacent molecules. ► Full agreement between STM images and theoretical simulations concerning shape and apparent height of molecules on the surface.