Ultrathin silica films immobilized on gold supports: Fabrication, characterization, and modification

Piotr Macech, Jeanne E Pemberton

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A novel method for covalent attachment of ultrathin silica films (thickness < 10 nm) to gold substrates is reported. Silica layers were prepared using spin-coating of sol-gel precursor solutions onto gold substrates that were cleaned and oxidized using UV photo-oxidation in an ozone atmosphere. The gold oxide layer resulting from this process acts as a wetting control and adhesive agent for the ultrathin silica layer. Control of silica layer thickness between ~6 and 60 nm through modification of precursor solution composition or by repetitive deposition is demonstrated. Films were characterized using infrared spectroscopy, ellipsometry, atomic force microscopy, and cyclic voltammetry. For the standard deposition parameters developed here, films were determined to be 5.5 ± 0.75 nm thick, and were stable in aqueous solutions ranging in pH from 2 to 10 for at least 30 min. Films contained nanoscopic defects with radii of ≤ 2 μm in all cases, at a density of 1.6 defects per 10 μm × 10 μm region, with a weighted average defect radius of 200 nm. This array of defects was shown to exhibit a voltammetric response consistent with an ultramicroelectrode array. Finally, ultrathin silica films were also modified with self-assembled monolayers of octadecylsilane, demonstrating the surface chemistry of bulk silica.

Original languageEnglish (US)
Pages (from-to)9816-9822
Number of pages7
JournalLangmuir
Volume23
Issue number19
DOIs
StatePublished - Sep 11 2007

Fingerprint

Silicon Dioxide
Gold
Silica
gold
silicon dioxide
Fabrication
fabrication
Defects
defects
radii
Photooxidation
photooxidation
Ozone
Ellipsometry
Spin coating
Self assembled monolayers
Substrates
Surface chemistry
Oxides
adhesives

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Ultrathin silica films immobilized on gold supports : Fabrication, characterization, and modification. / Macech, Piotr; Pemberton, Jeanne E.

In: Langmuir, Vol. 23, No. 19, 11.09.2007, p. 9816-9822.

Research output: Contribution to journalArticle

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