Highly site-specific H2 adsorption on Vicinal Si(001) surfaces

Reviews and Highlights	Quantum Science	Molecular and Soft-matter	Ultrafast Nano-optics and Nanophotonics	Mineralogy and Geochemistry

Peter Kratzer, Eckhard Pehlke, Matthias Scheffler, Markus B. Raschke, and Ulrich Höfer
Phys. Rev. Lett. 81, 5596 (1998).
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Experimental and theoretical results for the dissociative adsorption of H₂ on vicinal Si(001) surfaces are presented. Using optical second-harmonic generation, sticking probabilities at the step sites are found to exceed those on the terraces by up to 6 orders of magnitude. Density functional theory calculations indicate the presence of direct adsorption pathways for monohydride formation but with a dramatically lowered barrier for step adsorption due to an efficient rehybridization of dangling orbitals.