LEED studies of atomic structures of Si[l brace]111[r brace] [radical]3 [times] [radical]3-30[degrees]-metal surface phases. [LEED (low-energy electron diffraction)]

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7236259

Quinn, J E

The atomic structure of several Si(111)[radical]3 x [radical]3 - 30[degrees] - metal surfaces has been investigated using dynamical low-energy electron diffraction. A LEED intensity analysis of the Si(111)[radical]3 x [radical]3 - 30[degrees] - B surface has determined that boron atoms replace second-layer Si atoms and a Si adatom is located above each boron atom, the B[sub 5] site. The ideal coverage of this structure is 1/3 of a monolayer of boron atoms and the surface is relaxed. the Si(111)[radical]3 x [radical]3 - 30[degrees] - Mg surface could not be formed; the Si(111)2/3[radical]3 x 2/3[radical]3 - 30[degrees] - Mg surface could, however, be created and is most likely that of a reacted silicide. The formation of a Si(111)3 x 1 - Mg surface is reported with LEED I(V) spectra essentially identical to those of Si(111)3 x 1 - Li, -Na, and -Ag. Therefore, these metal atoms induce the formation of the Si(111)3 x 1 surface structure and are not ordered in the unit cell. The surface structure of the Si(111)[radical]3 x [radical]3 - 30[degrees] - Au surface has been determined to involve a coverage of one monolayer of Au. The Au atoms are chemisorbed on top of the substrate surface in the form of trimers, with the trimer centers located above the position of fourth-layer Si atoms, and the Au atoms are on off-first-layer Si sites. The first layer of Si atoms is missing and the second-layer Si atoms are displaced 0.5 [angstrom] away from the center of symmetry. Si(111)[radical]3 x [radical]3 - 30[degrees] - Ce and 2 x 1 - Ce surfaces have been formed and are most likely those of a silicide.

• Research Organization: State Univ. of New York, Stony Brook, NY (United States)
• OSTI ID: 7236259
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
664000 -- Atomic & Molecular Physics-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ALKALINE EARTH METALS
BORON
CHEMICAL REACTIONS
CHEMISORPTION
COHERENT SCATTERING
DIFFRACTION
ELECTRON DIFFRACTION
ELEMENTS
GOLD
LITHIUM
MAGNESIUM
METALS
MOLECULAR STRUCTURE
SCATTERING
SEMIMETALS
SEPARATION PROCESSES
SILICIDES
SILICON
SILICON COMPOUNDS
SODIUM
SORPTION
SURFACES
TRANSITION ELEMENTS