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Keywords:

  • dealloying;
  • dewetting;
  • nanoporous gold;
  • solid–liquid–solid growth

Abstract

Ordered arrays of nanoporous gold nanoparticles were fabricated via a combination of solid-state dewetting of Au/Ag bilayers on pre-patterned SiO2/Si substrates and a subsequent dealloying process. Au[BOND]Ag alloy nanoparticles were formed after dewetting, and a subsequent dealloying process leads to the formation of nanoporous gold nanoparticles. The dewetting was carried at 700, 800, and 900 °C, respectively. The growth of Si or silicide particles occurred after dewetting at 800 and 900 °C, and these particles remains even after the dealloying process. This growth is supposed to occur via a solid–liquid–solid (SLS) mechanism, and mainly Ag serves as catalyst. A 20 nm thick thermal SiO2 is sufficient to avoid this reaction between the Au/Ag bilayers and the Si substrate when the dewetting temperature is 700 °C.