THE ADSORPTION OF I2 ON SI(111)-7X7 STUDIED BY SOFT-X-RAY PHOTOEMISSION
1993 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 296, no 3, 383-392 p.Article in journal (Refereed) Published
The adsorption Of I2 on Si(111)-7 x 7 at room temperature is studied with soft X-ray photoelectron spectroscopy. I2 adsorbs dissociatively, forming a mixture of SiI, SiI2 and SiI3 moieties, of which SiI dominates. The Fermi level is pinned near mid-gap, moving slightly towards the conduction band as the I coverage increases. The surface work function increases monotonically with I coverage. The I 4d core-level displays a single chemical state, which decreases in binding energy with increasing coverage. Analysis of the Si 2p core-level spectra shows that the adsorption proceeds first by attachment of I to the dangling bonds of the 7 x 7 unit cell and that, at saturation, 1.57 +/- 0.05 ML of I atoms are adsorbed in 1.10 +/- 0.02 ML of SiI(x) groups. These results indicate that substrate Si-Si bonds are broken by reaction with I2. The total I coverage is limited, however, by the availability Of surface dangling bonds that are required to initiate the dissociation Of I2 molecules.
Place, publisher, year, edition, pages
1993. Vol. 296, no 3, 383-392 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-84191DOI: 10.1016/0039-6028(93)90032-FISI: A1993ME33300012OAI: oai:DiVA.org:kth-84191DiVA: diva2:499271
NR 201408052012-02-132012-02-132012-02-13Bibliographically approved