Complex patterned gold structures fabricated via laser annealing and dealloying

Gold films with periodic stripes of nanoporous structure are realized by using pulsed laser annealing in a mask projection arrangement in combination with a dealloying process. An Ag-Au alloy is first formed in the exposed areas of Ag/Au bi-layers by annealing, and then the Ag is removed from Ag-Au alloy by submerging in HNO3 solution and nanoporous gold is formed. The Ag top-layer in the unexposed areas of the Ag/Au bi-layers is also removed and the Au under-layer remains. Laser annealing is performed with 2 pulses and 10 pulses at different energy densities. Optimized laser annealing parameters for the 140 nm Ag/80 nm Au bi-layers is found with 10 pulses at fluences of 132 and 143 mJ/cm2.