Nickel-containing nano-sized islands grown on Ge (111)-c(2 × 8) and Ag/Ge(111)-(√3 × √3) surfaces

Tsu Yi Fu, Agnieszka Tomaszewska, Xiao Lan Huang, Jhen Hao Li, Po I. Hsieh, Ming Kuan Jhou

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Abstract

The formation of nano-islands on both a Ge(111)-c(2 × 8) surface and an Ag/Ge(111)-(√3 × √3) surface evaporated with 0.1 ML Ni was investigated by scanning tunneling microscopy (STM). We have noticed that at temperatures lower than 670 K, the reaction between Ni and the individual substrate surfaces proceeds to form different structures: flat-topped islands with a 2√7 × 2√7 or a 3 × 3 reconstruction on the Ni/Ge(111)-c(2 × 8) surface vs. islands with a 7 × 7 reconstruction on the Ni/Ag/Ge(111)-(√3 × √3) surface. From this we have inferred that within a temperature range between room temperature and 670 K, the intermediate Ag layer retards mixing between Ni and Ge atoms. As a result, the grown islands are composed of pure Ni atoms. Within a temperature range from 670 to 770 K, most islands produced on the Ag/Ge(111)-(√3 × √3) surface are identical with those formed on the Ni/Ge (111)-c(2 × 8) surface, suggesting that above 670 K, Ni atoms are likely to bind with Ge atoms. However, an essential difference between STM images of the surfaces under study exists in the appearance of large elongated islands on the Ni/Ag/Ge(111)-(√3 × √3) surface. The formation of the latter is explained in terms of a difference in energy for Ni diffusion on the Ge(111)-c(2 × 8) and Ag/Ge(111)-(√3 × √3) surfaces.

Original languageEnglish
Article number416
Pages (from-to)1-8
Number of pages8
JournalNanoscale Research Letters
Volume8
Issue number1
DOIs
Publication statusPublished - 2013 Jan 1

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Keywords

  • Ag
  • Ge(111)
  • Ni
  • STM

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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