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.