Sub-10 nm Au-Ag Heterogeneous Plasmonic Nanogaps

Controlling the formation of bimetallic heterogeneous nanogaps structures have many applications in the plasmonics and catalysis fields. Here, a simple and systematic method is developed to fabricate tunable and stable Au-Ag nanowire-based plasmonic metamaterials. The sub-10 nm Au-Ag bimetallic heterogeneous nanogaps with desirable optical properties are fabricated by a simple, ultrarapid, and robust nanoskiving technique. Compared to the monometallic linear Ag-Ag and Au-Au nanogaps, the Au-Ag bimetallic heterogeneous nanogaps exhibit remarkable surface enhanced Raman spectroscopy (SERS) enhancement properties due to the nanogaps between the adjacent Au/Ag nanowires, and the Ag/Au bimetallic composite film. In addition, 3D bimetallic heterogeneous nanogaps are built and produce much stronger electric fields than those of the 1D linear nanogaps. The sub-10 nm Au-Ag heterogeneous nanogaps are promising to be used in SERS substrate, plasmon devices, catalysis, and printed electronics.