Dealloying of Au-Ag thin films with a composition gradient: Influence on morphology of nanoporous Au

X. Lu, T. J. Balk, R. Spolenak, E. Arzt

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Nanoporous Au can be formed by dealloying Au-Ag alloys and, depending on the initial alloy composition, produce a variety of microstructural features. We investigated a wide compositional range and found three regimes, based on initial Au content, that yield varying degrees of dealloying in thin films. Between 22 and 26 at.% Au, dealloying produces nearly pure Au with an open nanoporous structure. However, above 36 at.% Au, only the grain boundaries dealloy, leaving islands of retained Au-Ag alloy. For intermediate compositions, a transitional microstructure results, with final Ag concentration ranging from 50 at.% down to 4 at.%. Film cracking was observed after dealloying, and lower initial Au content correlated with a higher degree of cracking and a higher pore fraction.

Original languageEnglish
Pages (from-to)7122-7126
Number of pages5
JournalThin Solid Films
Issue number18
StatePublished - Jun 25 2007

Bibliographical note

Funding Information:
The authors wish to thank Mr. R. Völker for thin film deposition and Mrs. S. Kühnemman for SEM examination. One of the authors (X. Lu) would like to express thanks to the Chinese Scholarship Council for financial support during his stay in Stuttgart.


  • Dealloy
  • Gold
  • Microstructure
  • Nanoporous
  • Porosity
  • Thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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