Silicon growth at the two-dimensional limit on Ag(111)

Andrew J. Mannix, Brian Kiraly, Brandon L. Fisher, Mark C. Hersam, Nathan P. Guisinger

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Having fueled the microelectronics industry for over 50 years, silicon is arguably the most studied and influential semiconductor. With the recent emergence of two-dimensional (2D) materials (e.g., graphene, MoS2, phosphorene, etc.), it is natural to contemplate the behavior of Si in the 2D limit. Guided by atomic-scale studies utilizing ultrahigh vacuum (UHV), scanning tunneling microscopy (STM), and spectroscopy (STS), we have investigated the 2D limits of Si growth on Ag(111). In contrast to previous reports of a distinct sp2-bonded silicene allotrope, we observe the evolution of apparent surface alloys (ordered 2D silicon-Ag surface phases), which culminate in the precipitation of crystalline, sp3-bonded Si(111) nanosheets. These nanosheets are capped with a √3 honeycomb phase that is isostructural to a √3 honeycomb-chained-trimer (HCT) reconstruction of Ag on Si(111). Further investigations reveal evidence for silicon intermixing with the Ag(111) substrate followed by surface precipitation of crystalline, sp 3-bonded silicon nanosheets. These conclusions are corroborated by ex situ atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Even at the 2D limit, scanning tunneling spectroscopy shows that the sp3-bonded silicon nanosheets exhibit semiconducting electronic properties.

Original languageEnglish
Pages (from-to)7538-7547
Number of pages10
JournalACS nano
Volume8
Issue number7
DOIs
Publication statusPublished - Jul 22 2014

Keywords

  • molecular beam epitaxy
  • scanning tunneling microscopy
  • silicene
  • surface reconstruction
  • two-dimensional materials

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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    Mannix, A. J., Kiraly, B., Fisher, B. L., Hersam, M. C., & Guisinger, N. P. (2014). Silicon growth at the two-dimensional limit on Ag(111). ACS nano, 8(7), 7538-7547. https://doi.org/10.1021/nn503000w