Fabrication of arrays of metal and metal oxide nanotubes by shadow evaporation

Michael D. Dickey, Emily A. Weiss, Elizabeth J. Smythe, Ryan C. Chiechi, Federico Capasso, George M. Whitesides

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

This paper describes a simple technique for fabricating uniform arrays of metal and metal oxide nanotubes with controlled heights and diameters. The technique involves depositing material onto an anodized aluminum oxide (AAO) membrane template using a collimated electron beam evaporation source. The evaporating material enters the porous openings of the AAO membrane and deposits onto the walls of the pores. The membrane is tilted with respect to the column of evaporating material, so the shadows cast by the openings of the pores onto the inside walls of the pores define the geometry of the tubes. Rotation of the membrane during evaporation ensures uniform deposition inside the pores. After evaporation, dissolution of the AAO in base easily removes the template to yield an array of nanotubes connected by a thin backing of the same metal or metal oxide. The diameter of the pores dictates the diameter of the tubes, and the incident angle of evaporation determines the height of the tubes. Tubes up to ∼ 1.5 μm in height and 20 -200 nm in diameter were fabricated. This method is adaptable to any material that can be vapor-deposited, including indium - tin oxide (ITO), a conductive, transparent material that is useful for many opto-electronic applications. An array of gold nanotubes produced by this technique served as a substrate for surface-enhanced Raman spectroscopy: the Raman signal (per molecule) from a monolayer of benzenethiolate was a factor of ∼ 5 × 105 greater than that obtained using bulk liquid benzenethiol.

Original languageEnglish
Pages (from-to)800-808
Number of pages9
JournalACS nano
Volume2
Issue number4
DOIs
Publication statusPublished - Apr 1 2008

Keywords

  • AAO (anodized aluminum oxide)
  • ITO (indium-tin oxide)
  • Line-of-sight deposition
  • Nanofabrication
  • Nanotube arrays
  • SERS (surface-enhanced Raman spectroscopy)
  • Shadow evaporation
  • Templated fabrication

ASJC Scopus subject areas

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

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  • Cite this

    Dickey, M. D., Weiss, E. A., Smythe, E. J., Chiechi, R. C., Capasso, F., & Whitesides, G. M. (2008). Fabrication of arrays of metal and metal oxide nanotubes by shadow evaporation. ACS nano, 2(4), 800-808. https://doi.org/10.1021/nn800036r