Transition from single- to multi-layered structures in nanoporous gold-palladium ultrathin films

The transition from single- to multi-layered structures in nanoporous films was investigated in nanoporous gold-palladium (np-AuPd) ultrathin films. Configuration and contact behavior of AuPd ligaments in porous layers were characterized with patterned or curved np-AuPd films. In a multi-layered structure, AuPd ligaments in the layer closest to the substrate exhibit a different configuration than in a single-layered structure. This transition is discussed in relation to film thickness, volume contraction and bonding with the substrate.