A single bottom facet outperforms random multifacets in a nanoparticle-on-metallic-mirror system.

Area of Science:

• Plasmonics
• Nanotechnology
• Materials Science

Background:

• Nanoparticle-on-metallic-mirror (NPOM) systems are crucial for plasmonic enhancement.
• Achieving efficient NPOMs with large gaps requires careful design, especially with spherical nanoparticles.

Purpose of the Study:

• To investigate a new design blueprint for optimizing NPOMs using spherical nanoparticles.
• To evaluate the impact of random facets versus single facets in NPOMs.

Main Methods:

• Investigated the role of random facets in spherical nanoparticles for NPOM design.
• Utilized three-dimensional surface charge density mappings to interpret plasmonic modes.
• Fabricated single bottom-faceted NPOMs with large gap sizes and characterized their performance.

Main Results:

• A single, precisely positioned facet in the nanoparticle cavity significantly outperformed multiple random facets.
• The optimized single bottom-faceted NPOM achieved excellent gap mode enhancement with a large gap size (20 nm).
• Successfully fabricated large-scale (2 cm × 1.5 cm) single bottom-faceted NPOMs with high unidirectionality.

Conclusions:

• A single-faceted design is superior to random facets for maximizing gap mode contribution in NPOMs.
• The developed NPOM design demonstrates high efficiency and large gap enhancement for practical applications.
• This research paves the way for advanced applications in quantum emitters, energy, and plasmon chemistry.