Local surface structures of c(2 x 2) S/Ni(011) and (2 x 2) S/Ge(111) determined using ARPEFS

Technical Report · Tue Apr 01 04:00:00 EST 1986

OSTI ID:5635092

Robey, S W

Angle-resolved photoemission extended fine structure (ARPEFS) measurements were performed on the c(2 x 2) S/Ni(011) and (2 x 2) S/Ge(111) systems. The S/Ni(011) system was studied to assess the extent to which surface structural information can be obtained from ARPEFS and to provide a large data set for comparison to recently developed multiple-scattering calculations. An expansion of the first Ni interplanar separation (11%) previously indicated by ion scattering experiments was confirmed, and a further reconstruction consisting of a buckled second Ni layer was suggested the S/Ge(111) study. Results of the ARPEFS investigation on the S/Ge(111) system indicate that sulfur adsorbs on Ge(111) in a 2-fold bridge site, 1.03 +- 0.05 A above the first Ge layer. This is different from the site determined for Te/Ge(111), but agrees with the adsorption sites proposed for Te/Si(111) and Se/Si(111). The data also indicate a contraction (9%) in the first interplanar separation (the separation of the two components of the first bilayer), and an expansion of 7 +- 3% in the bond lengths between the Ge bilayers (2.60 to 2.65 A versus a bulk value of 2.45 A). This last result applies to the bonds which are most nearly below the 2-fold adsorption site.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5635092
• Report Number(s): LBL-21468; ON: DE86012495
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ADSORPTION
ELEMENTS
EMISSION
FINE STRUCTURE
FOURIER TRANSFORMATION
GERMANIUM
INTEGRAL TRANSFORMATIONS
LAYERS
METALS
NICKEL
NONMETALS
PHOTOEMISSION
SCATTERING
SECONDARY EMISSION
SORPTION
SORPTIVE PROPERTIES
SULFUR
SURFACE PROPERTIES
SURFACES
TRANSFORMATIONS
TRANSITION ELEMENTS