Spectrally broad plasmonic absorption in Ga and In nanoparticle hybrids.

In this work, we use Joule-effect thermal evaporation to produce hybrid structures made of Ga and In nanoparticles (NPs) on Si (100) substrates. Taking advantage of the protective oxide shell, In NPs can be used as a template for a second deposition step without structural changes, enabling the hybridization of NPs of materials. These complex structures of mixed NPs present a spectrally broad plasmonic absorption that can be optically tuned with a wide range of photon energies from UV to IR regions with a full width at half maximum range of ∼400 to 800 nm. The results suggest that the localized surface plasmon resonance (LSPR) of the hybrid NPs is mainly due to the plasmonic coupling of the in-plane modes. Furthermore, different scenarios studied by discrete dipole approximation simulations show that the interconnection between NPs is extremely sensitive to the size and the local arrangement of the nanostructures. This kind of broadening and tunable LSPR may have interest for energy transfer applications, biosensing platforms and solar cells.