Investigation of dealloying in Au-Ag thin films by quantitative electron probe microanalysis

Dealloying of Au–Ag films has been investigated by quantitative electron probe microanalysis and scanning electron microscopy. For film compositions greater than 44 at.% Au, dissolution of Ag is limited, with individual pores distributed randomly on the surface. Dealloying is enhanced as the initial Au content decreases below 44 at.%. The dealloying threshold, or parting limit, below which the fully nanoporous structure evolves, is 35 at.% Au. Dealloying also causes a slight decrease in film thickness, which is readily measured using the technique discussed here.