Ultrasmall Plasmonic Single Nanoparticle Light Source Driven by a Graphene Tunnel Junction

Area of Science:

• Plasmonics
• Nanophotonics
• Materials Science

Background:

• Metal nanoparticles are key for nano-optics, enabling light coupling into surface plasmons.
• Existing studies focus on light scattering/concentration, with limited research on intrinsic plasmonic light emission.
• Inelastic electron tunneling for plasmonic light emission is difficult with isolated nanoparticles due to electrical connection challenges.

Purpose of the Study:

• To develop a method for efficient light emission from individual plasmonic nanoparticles.
• To overcome limitations of electrical contacting for single nanoparticle plasmon excitation.
• To explore scalable fabrication of plasmonic light-emitting nanostructures.

Main Methods:

• Utilizing gold nanoparticles placed on a graphene tunnel junction.
• Employing monolayer graphene as a transparent counter electrode for electron tunneling.
• Exciting plasmonic modes via tunneling electrons followed by radiative decay.
• Tuning light emission using a dielectric overlayer.

Main Results:

• Achieved electroluminescence from single gold nanoparticles without bulky contacts.
• Demonstrated scalability by creating millimeter-sized arrays of nanoparticles.
• Confirmed that tunneling electrons excite plasmonic modes, leading to light emission.

Conclusions:

• The gold nanoparticle-graphene tunnel junction approach offers a simple and scalable method for plasmonic light emission.
• This technique overcomes previous limitations in electrically exciting single plasmonic nanoparticles.
• The developed method paves the way for new applications in nanophotonics and optoelectronics.