Tripling the light extraction efficiency of a deep ultraviolet LED using a nanostructured p-contact

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Deep ultra-violet light emitting diodes (DUV LEDs) suffer from low efficiencies compared to other light-emitting devices.
• Low light extraction efficiency in DUV LEDs is attributed to highly absorbing p-contacts and total internal reflection.

Purpose of the Study:

• To propose and investigate a novel nanostructured p-contact design to enhance light extraction efficiency in DUV LEDs.
• To reduce light absorption in the p-contact layer and improve light emission.

Main Methods:

• Fabrication of a multi-layered p-contact featuring a hexagonal periodic array of platinum-filled cylindrical nanoholes.
• Comparison of light extraction efficiency between the nanostructured p-contact and a planar reference structure.
• Analysis of the nanostructure's impact on light absorption and total internal reflection.

Main Results:

• The optimized nanostructure achieved a light extraction efficiency of 15.0%, a significant improvement over the planar reference's 4.6%.
• The nanostructure effectively reduced light absorption within the p-contact layer.
• The nanostructure did not substantially mitigate total internal reflection.

Conclusions:

• The proposed nanostructured p-contact offers a readily implementable strategy for enhancing DUV LED light extraction efficiency.
• Combining this nanostructure with other optical techniques, like nanopatterned sapphire substrates, could further boost overall device efficiency.
• This work presents a viable path towards improving state-of-the-art DUV LED performance.