Complex chiral colloids and surfaces via high-index off-cut silicon

Kevin M. McPeak, Christian D. Van Engers, Mark Blome, Jong Hyuk Park, Sven Burger, Miguel A. Gosálvez, Ava Faridi, Yasmina R. Ries, Ayaskanta Sahu, David J. Norris

Research output: Contribution to journalArticlepeer-review


Silicon wafers are commonly etched in potassium hydroxide solutions to form highly symmetric surface structures. These arise when slow-etching {111} atomic planes are exposed on standard low-index surfaces. However, the ability of nonstandard high-index wafers to provide more complex structures by tilting the {111} planes has not been fully appreciated. We demonstrate the power of this approach by creating chiral surface structures and nanoparticles of a specific handedness from gold. When the nanoparticles are dispersed in liquids, gold colloids exhibiting record molar circular dichroism (>5 × 10 9 M-1 cm-1) at red wavelengths are obtained. The nanoparticles also present chiral pockets for binding.

Original languageEnglish (US)
Pages (from-to)2934-2940
Number of pages7
JournalNano Letters
Issue number5
StatePublished - May 14 2014


  • Chiral nanoparticles
  • anisotropic etching
  • circular dichroism
  • gold colloids
  • localized surface plasmons

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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