Formation of Nanogrooves with Sub-5 nm Periodicity Using Local Silicification at the Interspace between a Si Substrate and Lyotropic Liquid Crystals

Shintaro Hara, Hiroaki Wada, Atsushi Shimojima, Kazuyuki Kuroda

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Bottom-up fabrication of nanopatterns with single nanometer-scale periodicity is quite challenging. In this study, we have focused on the use of the outermost convex surfaces of lyotropic liquid crystals (LLCs) as a template. Periodically arrayed single nanometer-scale nanogrooves consisting of silica are successfully formed on a Si substrate covered with LLCs composed of cylindrical micelles of cetyltrimethylammonium chloride. Soluble silicate species are generated from the Si substrate by a treatment with an NH3-water vapor mixture, infilling the interspaces between the Si substrate and the LLCs. The cross section of the nanogrooves has a symmetrical sawtooth-like profile with a periodicity of 4.7 nm, and the depth of each nanogroove is around 2 nm. Uniaxial alignment of the nanogrooves can be achieved using micrometer-scale grooves fabricated by a focused ion beam technique. Although formed nanogrooves contain defects, such as bends and discontinuities, this successful concept provides a novel fabrication method of arrayed concave patterns with sub-5 nm periodicity on the surfaces of Si substrates.

Original languageEnglish
Pages (from-to)5160-5166
Number of pages7
JournalACS Nano
Volume11
Issue number5
DOIs
Publication statusPublished - 2017 May 23

Keywords

  • liquid crystals
  • nanoimprint mold
  • nanopattern
  • silicification
  • template

ASJC Scopus subject areas

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

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