Fabrication of Mo pyramidal-shape single atom tips covered by a noble metal

Rung Jiun Lin, Yi Ju Chen, Hsiao Chi Chen, Tsu Yi Fu

Research output: Contribution to journalArticle

Abstract

The effect of annealing temperature on the faceting phenomena has been studied for pure molybdenum (Mo) and Mo tips covered with palladium (Pd), platinum (Pt), rhodium (Rh), or iridium (Ir) by field ion microscopy (FIM). For these Mo samples, three {2 1 1} facets were found to expand to {1 1 1} facets and form pyramidal structures after annealing at the temperature of 1100-1300 K. The pyramidal single atom tips (SATs) were formed on Pd-, Pt- and Rh-covered Mo tips. Two types of pyramidal structure, stacked by either 1, 3, 10 or 1, 6, 15 atoms for the top three layers were found. However, no SATs were found on pure Mo and Ir-covered tips. This indicates that noble metal adsorption, which can increase the difference of surface-free-energy anisotropy, indeed benefits the formation of SATs on Mo systems. Additionally, an SAT cannot be obtained for the Ir-covered Mo systems, because Ir is easily alloyed with Mo.

Original languageEnglish
Pages (from-to)90-94
Number of pages5
JournalApplied Surface Science
Volume309
DOIs
Publication statusPublished - 2014 Aug 1

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Keywords

  • Adsorbate-induced faceting
  • Field ion microscope
  • Molybdenum
  • Single atom tips

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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