Formation and structure of a (√19 × √19)R23.4°-Ge/Pt(1 1 1) surface alloy

Chih Sung Ho, Santanu Banerjee, Matthias Batzill, David E. Beck, Bruce E. Koel

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17 Scopus citations


An ordered (√19 × √19)R23.4°-Ge/Pt(1 1 1) surface alloy can be formed by vapor depositing one-monolayer Ge on a Pt(1 1 1) substrate at room temperature and subsequently annealing at 900-1200 K. The long-range order of this structure was observed by low energy electron diffraction (LEED) and confirmed by scanning tunneling microscopy (STM). The local structure and alloying of vapor-deposited Ge on Pt(1 1 1) at 300 K was investigated by using X-ray Photoelectron Diffraction (XPD) and low energy alkali ion scattering spectroscopy (ALISS). XPS indicates that Ge adatoms are incorporated to form an alloy surface layer at ∼900 K. Results from XPD and ALISS establish that Ge atoms are substitutionally incorporated into the Pt surface layer and reside exclusively in the topmost layer, with excess Ge diffusing deep into the bulk of the crystal. The incorporated Ge atoms at the surface are located very close to substitutional Pt atomic positions, without any corrugation or "buckling". Temperature Programmed Desorption (TPD) shows that both CO and NO adsorb more weakly on the Ge/Pt(1 1 1) surface alloy compared to that on the clean Pt(1 1 1) surface.

Original languageEnglish (US)
Pages (from-to)1161-1167
Number of pages7
JournalSurface Science
Issue number9
StatePublished - May 1 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry


  • Alkali ion scattering
  • Alloy
  • Germanium
  • Low energy electron diffraction
  • Low energy ion scattering
  • Platinum
  • Scanning tunneling microscopy
  • X-ray photoelectron diffraction


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