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Title: Core-level photoemission study of thallium adsorbed on a Si(111)-(7x7) surface: Valence state of thallium and the charge state of surface Si atoms

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
;  [1]; ;  [2]; ;  [3]
  1. Graduate School of Science and Technology, Chiba University, Chiba 263-8522 (Japan)
  2. Department of Physics, Chemistry and Biology, Linkoeping University, S-581 83 Linkoeping (Sweden)
  3. Department of Molecular and Material Sciences, Kyushu University, Fukuoka 816-8580 (Japan)

The coverage-dependent valence state of Tl adsorbed on a Si(111)-(7x7) surface and the coverage dependence of the charge states of surface Si atoms have been investigated by high-resolution core-level photoelectron spectroscopy. Although two different reconstructions were observed in low-energy electron diffraction at different coverages, a (1x1) pattern at a Tl coverage of 1 monolayer (ML) and a ({radical}(3)x{radical}(3)) pattern at a coverage of 1/3 ML, the binding energy of the Tl 5d core-level was the same at Tl coverages up to 1 ML. Taking the valence state on a (1x1) surface reported in the literature into account, we conclude that the valence state of Tl is 1+, and that the 6s{sup 2} electrons of Tl are inactive as an inert pair in the Tl-Si bonding on a Si(111) surface at a coverage of 1 ML and below. In the Si 2p core-level spectra, one surface component was observed on the (1x1) surface, and three surface components were observed on the ({radical}(3)x{radical}(3)) surface. The binding energies and intensities of the Si 2p surface components indicate that the charge state of the surface Si atoms on Tl/Si(111)-(1x1) is the same as that of the ({radical}(3)x{radical}(3)) surfaces induced by the other group III metals, but they are different on the Tl/Si(111)-({radical}(3)x{radical}(3)) surface.

OSTI ID:
20853552
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 74, Issue 7; Other Information: DOI: 10.1103/PhysRevB.74.075335; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
Country of Publication:
United States
Language:
English