Spectrally Pure, High Operational Dynamic Range, Deep Red Micro-LEDs

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• III-nitride micro-light-emitting diodes (micro-LEDs) are crucial for next-generation displays and AR/VR.
• Achieving efficient, stable, and microscale red-emitting III-nitride micro-LEDs remains a significant challenge for full-color applications.

Purpose of the Study:

• To develop pure red-emitting III-nitride micro-LEDs with high efficiency and spectral stability.
• To overcome limitations in current red micro-LED technology for advanced display applications.

Main Methods:

• Detailed strain engineering and precise control of charge carrier transport.
• Utilizing a short-period InGaN/GaN superlattice combined with a thick n-type GaN interlayer.
• Theoretical and experimental validation of the device design and performance.

Main Results:

• Achieved pure red emission (≥620 nm) across a wide range of injection currents (over two orders of magnitude).
• Demonstrated deep red micro-LEDs (∼1 μm lateral dimension) with a peak external quantum efficiency exceeding 3% at ∼660 nm.
• Successfully relieved the quantum-confined Stark effect and suppressed parasitic superlattice emission.

Conclusions:

• The developed strain engineering and charge transport control strategies are effective for high-performance red III-nitride micro-LEDs.
• The optimized device design enables stable and efficient pure red emission, paving the way for full-color micro-LED displays.
• This work addresses a critical bottleneck in III-nitride micro-LED technology, advancing AR/VR and display capabilities.