Altered photoemission satellites at CaF{sub 2}- and SrF{sub 2}-on-Si(111) interfaces

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.1584· OSTI ID:278533

Rotenberg, E ^[1]; Denlinger, J D ^[2]; Olmstead, M A ^[3]

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1. Department of Physics, University of Oregon, Eugene, Oregon 97403 (United States)
2. Department of Physics, University of Wisconsin, Milwaukee, Wisconsin 53211 (United States)
3. Department of Physics, P.O. Box 351560, University of Washington, Seattle, Washington 98195-1560 (United States)

Bulk and interface photoemission satellite excitations, measured with x-ray photoelectron spectroscopy and x-ray photoelectron diffraction, are compared for thick, thin, and monolayer films of CaF{sub 2} and SrF{sub 2} on Si(111). Intrinsic satellites are observed for excitation of atoms in the first monolayer, both uncovered and at the buried interface, that differ from those associated with bulk atoms. For F 1{ital s} excitation, the bulk and interface satellites differ only in width and amplitude; for the cation core excitations (Ca 2{ital p}, Sr 3{ital p}, and Sr 3{ital d}), the observed excitation energies and intensities differ both from the equivalent bulk satellites and among the various core hole states. The results yield new information on the nature of the interface bonding, as well as on the origin of both bulk and interface satellites. Several models are considered, including differential screening, dielectric losses, crystal-field and multiplet effects, and interface excitation. The most likely explanation for the new cation satellites at the CaF{sub 2}/Si(111) [SrF{sub 2}/Si(111)] interface is localized excitation of the interface bond, where the interface band gap is controlled by the collapse of the Ca 3{ital d} (Sr 4{ital d}) level in the presence of the Ca (Sr) core hole. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 278533
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 3 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM FLUORIDES
CORE LEVELS
ENERGY GAP
INTERFACES
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
SILICON
STRONTIUM FLUORIDES
X RADIATION