A scattered volume emitter micropixel architecture for ultra efficient light extraction from DUV LEDs

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Photonics

Background:

• Deep ultraviolet light-emitting diodes (DUV LEDs) face challenges with parasitic absorption and light loss due to oblique emission angles from multiple quantum wells (MQWs).
• Conventional DUV LED designs often require high-index substrates or surface texturing for efficient light extraction, adding complexity and cost.

Purpose of the Study:

• To propose and evaluate a novel DUV LED architecture that enhances light extraction efficiency by utilizing oblique emission angles.
• To demonstrate a DUV LED design that achieves high efficiency without relying on high-index substrates, lenses, or nanotextured epitaxial layers.

Main Methods:

• Utilized spaced-apart or scattered volume emitter micropixels embedded in a low-index dielectric buffer film with a patterned top surface.
• Employed hybrid wave and ray optical simulations to model light extraction efficiency.
• Compared the proposed architecture against conventional planar LED designs and nanotextured DUV LEDs.

Main Results:

• Achieved a three to sixfold increase in light extraction efficiency compared to conventional planar DUV LEDs with sapphire substrates.
• Demonstrated an extraction efficiency three times greater than a recent nanotextured DUV LED design.
• The proposed architecture does not require high-index substrates, lenses, or nanotextured epi layers.

Conclusions:

• The novel micropixel architecture effectively leverages oblique light emission for significantly improved light extraction efficiency in DUV LEDs.
• This approach offers a pathway to DUV LEDs with plug efficiencies comparable to mercury lamps in a much smaller form factor.
• The design eliminates the need for complex outcoupling structures, potentially simplifying DUV LED fabrication and reducing costs.