Atomic-scale study of the adsorption of calcium fluoride on Si(100) at low-coverage regime

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© 2011 American Physical Society (APS). This is the accepted version of the following article: Chiaravalloti, Franco ; Dujardin, Gérald ; Riedel, Damien ; Pinto, Henry P. ; Foster, Adam S.. 2011. Atomic-scale study of the adsorption of calcium fluoride on Si(100) at low-coverage regime. Physical Review B. Volume 84, Issue 15. 155433/1-7. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.84.155433, which has been published in final form at http://journals.aps.org/prb/pdf/10.1103/PhysRevB.84.155433.

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Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2011

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Mcode

Degree programme

Language

en

Pages

155433/1-7

Series

Physical Review B, Volume 84, Issue 15

Abstract

We investigate, experimentally and theoretically, the initial stage of the formation of Ca/Si and Si/F structures that occurs during the adsorption of CaF2 molecules onto a bare Si(100) surface heated to 1000 K in a low-coverage regime (0.3 monolayer). A low-temperature (5 K) scanning tunneling microscope (STM) is used to observe the topographies and the electronic properties of the exposed silicon surfaces. Our atomic-scale study reveals that several chemical reactions arise during CaF2 deposition, such as dissociation of the CaF2 molecules and etching of the surface silicon dimers. The experimental and calculated STM topographies are compared using the density functional theory, and this comparison enables us to identify two types of reacted structures on the Si(100) surface. The first type of observed complex surface structure consists of large islands formed with a semiperiodic sequence of 3 × 2 unit cells. The second one is made of isolated Ca adatoms adsorbed at specific sites on the Si(100)-2 × 1 surface.

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Keywords

silicon surfaces, CaF2 deposition, scanning tunneling microscope

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Citation

Chiaravalloti, Franco & Dujardin, Gérald & Riedel, Damien & Pinto, Henry P. & Foster, Adam S.. 2011. Atomic-scale study of the adsorption of calcium fluoride on Si(100) at low-coverage regime. Physical Review B. Volume 84, Issue 15. 155433/1-7. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.84.155433.