Micro-light emitting diodes (LEDs) based on gallium nitride (GaN) semiconductor materials perform efficiently for blue and green light in display applications but less optimally for red light emission. A design to improve red micro-LED emission intensity with gallium indium nitride (GaInN) nanopyramids has been engineered by researchers from Meijo University (Japan), Xiamen University (China) and Future Display Institute (China).
These nanopyramid structures are formulated with a core of n-GaN followed by multiple quantum shells of GaInN/GaN. The layering scheme addresses strain within the material, which is crucial for enhancing the efficiency of red light in microLEDs. The inclusion of an n-GaInN layer in the pyramid structure helps relieve the compressive strain that typically builds up in LEDs, especially when working with In. Strain in semiconductor materials can cause defects that limit the efficiency of light emission, so managing it effectively is essential.
Source: Appl. Surf. Sci. (2024) 679, 161219/10.1016
The core-shell structure allows for a better distribution of Indium, enhancing red light emission. The semipolar plane of the pyramid helps reduce the quantum-confined Stark effect, which distorts electric fields inside the LED and reduces its performance. The shape of the nanopyramids naturally aids in light extraction and helps light escape more easily, improving overall brightness and performance.
As reported in Applied Surface Science, the light output from the updated red micro-LED was 1.2 times brighter than its predecessors.
