Fabrication of crack-free nanoporous gold blanket thin films by potentiostatic dealloying

Nanoporous gold (NPG) is of interest due to its very high surface area to volume ratio. The fabrication of crack-free blanket NPG thin films on silicon substrates using standard clean room methods is reported. Ag–Au precursor alloys are deposited both by thermal vapor deposition as well as by sputter deposition. Dealloying is performed using two different electrochemical regimens, one with a stepped potential increase and the other with a ramped increase. The ramped increase gives better NPG film uniformity.