Effects of substrate curvature on dealloying of nanoporous thin films

Co-sputtered AuPdAg alloy films on flat and curved substrates were investigated to determine the effects of substrate curvature on dealloying and microstructure of nanoporous (np) AuPd. Ligament morphology, film cracking and composition were significantly different for np-AuPd in concave vs. convex film regions. Convex substrate curvature led to extensive film cracking, wide and high aspect ratio ligaments, and low residual Ag content. This is attributed to a more tensile stress state that enhances the dissolution rate of Ag.