Surface Plasmon Excited on Imprintable Thin-Film Metallic Glasses for Surface-Enhanced Raman Scattering Applications

Metallic glasses (MGs) are a class of amorphous alloys in contrast with crystalline metals and provide a challenge of engineering applications for unique structure and properties. However, plasmonic applications remain a virgin area for MGs. In this work, we discovered that certain compositions of gold-based MGs possessed negative dielectric constants and could be used as plasmonic materials. Furthermore, with a low glass-transition temperature of gold-based thin-film MGs (TFMGs), we were able to fabricate large dimensions of nanostructures using an inexpensive thermal imprint method in air instead of other costly lithography methods. We performed both measurements and simulations to demonstrate that our designed nanostructures were suitable for surface-enhanced Raman scattering (SERS) applications. In addition, in the absence of grain boundaries in amorphous TFMGs, damping due to increased scattering at grain boundaries does not occur, and SERS could be improved. Also, compared to regular SERS substrates...