Combining surface plasmonic and light extraction enhancement on InGaN quantum-well light-emitters

Area of Science:

• Optoelectronics and Nanotechnology
• Semiconductor Physics

Background:

• Indium Gallium Nitride (InGaN) light-emitting diodes (LEDs) suffer from low efficiency.
• Surface plasmon coupling and nano-patterning are known methods to enhance LED efficiency, but are typically used independently.
• Achieving simultaneous light extraction and internal quantum efficiency enhancement remains a challenge.

Purpose of the Study:

• To demonstrate a combined approach using dielectric nano-patterning and silver nanoparticles (NPs) to enhance InGaN/GaN quantum-well light-emitters.
• To investigate the synergistic effects of dielectric nano-patterns and Ag NPs on light extraction and internal quantum efficiency.
• To optimize plasmonic resonance for improved light emission.

Main Methods:

• Fabrication of dielectric nano-rod patterns on the GaN surface of InGaN/GaN quantum-well structures.
• Integration of silver nanoparticles (NPs) onto the nano-patterned surface.
• Analysis of emission components from both GaN and sapphire surfaces.
• Comparison of performance with planar surfaces.

Main Results:

• The dielectric nano-rod pattern acts as an optical coating, improving light extraction.
• The low refractive index of the dielectric pattern blue-shifts the plasmonic resonance of Ag NPs towards the InGaN emission wavelength.
• Ag NPs on the dielectric nano-pattern show significantly stronger enhancement compared to Ag NPs on a planar surface.
• Enhanced emission was observed from both GaN and sapphire interfaces.

Conclusions:

• The combined dielectric nano-patterning and Ag NP strategy effectively enhances both light extraction and internal quantum efficiency in InGaN LEDs.
• This integrated approach offers a promising pathway to overcome the efficiency limitations of InGaN light-emitters.
• The blue-shifting of plasmonic resonance by the dielectric pattern is crucial for maximizing efficiency gains.