Plasmon Mode-Selective Gold Nanodimers with a Metal-Semiconductor Hybrid Junction

Area of Science:

• Nanophotonics and Plasmonics
• Materials Science
• Optoelectronics

Background:

• Plasmonic dimers enable nanoscale light manipulation via hybridized modes like capacitive plasmons (CPs) and charge transfer plasmons (CTPs).
• Existing junctions are limited to noble metals, restricting fundamental understanding and design flexibility.

Purpose of the Study:

• To engineer a novel metal-semiconductor hybrid junction for plasmonic dimers.
• To achieve selective regulation of plasmonic modes by controlling the interparticle junction.

Main Methods:

• Fabrication of gold nanosphere dimers with a unique metal-semiconductor hybrid junction.
• Single-particle scattering measurements to analyze plasmonic mode behavior.
• Electromagnetic simulations to elucidate the underlying physical mechanisms.

Main Results:

• The hybrid junction, featuring Ag pathways in an AgI matrix, enhanced CPs and suppressed CTPs.
• Interfacial field localization in AgI, driven by induced dipoles, was identified as the key mechanism for mode selectivity.
• This mechanism effectively traps surface plasmons and hinders electronic conduction.

Conclusions:

• The developed hybrid junction provides a tunable platform for controlling plasmonic modes.
• This advancement opens new avenues for applications in surface-enhanced Raman spectroscopy, optothermal therapeutics, nanophotonics, and optoelectronics.