Kookmin University Researchers Achieve Breakthrough in Micro/Nano-LED Technology
Here’s a summary of the key findings from the provided text:
The Problem:
* Ultra-small micro/nano-LEDs (5μm or less) are promising for next-generation displays due to their high brightness, long lifespan, and energy efficiency.
* Though, shrinking chip size leads to increased defects (Shockley-Read-Hall – SRH & dangling bonds) during the manufacturing process (dry etching), causing a notable drop in luminous efficiency.
* Existing passivation methods (SiO·AlO coatings) only partially address the issue,failing to fundamentally solve the dangling bond problem.
The Solution:
* Researchers at Kookmin University, led by Professor Do Young-rak, developed a new technology called UV-irradiated moisture adsorption (UVIMA) surface control.
* This technology is integrated with a top-down nanoprocess-based Fin-LED structure.
* How it effectively works: UVIMA uses ultraviolet light to activate moisture in the air,which then chemically adsorbs to the LED surface,effectively stabilizing dangling bonds formed during etching.
* This process also activates a delayed luminescence mechanism, converting trapped electrons (previously lost to defects) back into light emission.
The Results:
* significant Efficiency Advancement: Sub-5μm InGaN/GaN Fin-LEDs achieved:
* Internal quantum efficiency of 70.9%
* External quantum efficiency of 16.5%
* Electroluminescence luminance of approximately 18,000 cd/m² – reaching industrial-level performance.
* Scalability: The Fin-LED structure can be assembled using dielectrophoretic technology, enabling ultra-high-resolution pixel manufacturing.
* Demonstrated Application: A 64×64 sub-pixel passive matrix image was successfully created, demonstrating potential for use in high-resolution displays, wristwatch displays, and automobile displays.
Significance:
* This research provides a key source technology to overcome the efficiency limitations of ultra-small LEDs.
* It paves the way for the commercialization of low-cost, high-efficiency micro/nano-LED displays.
* The UVIMA process offers a fundamental solution to the dangling bond problem, a major hurdle in the field.
In essence, the Kookmin University team has found a way to “heal” defects in ultra-small LEDs using UV light and moisture, dramatically improving their performance and bringing them closer to practical application.
Keep reading