In May of this year, King Abdullah University of Science and Technology (KAUST) announced the development of a new InGaN-based red light Micro LED chip. The external quantum efficiency (EQE) has been improved. LED displays play an important role in promoting. On this basis, KAUST has recently made new breakthroughs.
According to foreign media reports, KAUST has developed Micro LED (μLEDs) chips that can efficiently emit light in the entire visible light spectrum, realizing the full color of Micro LEDs. At present, related papers of the KAUST team have been published in the journal "Photonics Research".
According to reports, nitrogen alloy is a kind of semiconductor material, through the correct chemical mixing, can emit RGB three colors of light, help Micro LED to achieve RGB full-color display. However, when the size of the nitride chip is reduced to the micron level, the luminous efficiency will also become weaker.
The KAUST research team gave a detailed explanation: The main obstacle to reducing the size of the chip is that the sidewall of the LED structure will be damaged during the production process, and the occurrence of defects will cause leakage, which will affect the light emission of the chip. And, as the size shrinks, this phenomenon will become more obvious, so the size of the LED chip is limited to 400μm×400μm.
However, the KAUST team achieved a breakthrough in this problem and developed a high-brightness InGaN red micro LED chip with a size of 17μm×17μm.
It is reported that the research team used fully calibrated atomic deposition technology to develop a 10×10 red light Micro LED array, and through chemical treatment to eliminate the damage to the sidewall of the LED chip structure. Through atomic-level observations (professional tools and sample preparation are required), the research team confirmed that the sidewalls have high crystallinity after chemical treatment.
According to the research team’s observations, the output power per 2 square millimeter area of the chip surface is as high as 1.76 mW, while the output power per 2 square millimeter area of the previous product is only 1 mW. In contrast, the output power of the new product has been significantly improved, which means external The quantum luminous efficiency is significantly improved. Subsequently, the research team combined the red light Micro LED chip with the InGaN blue and green light Micro LED chip to produce a wide color gamut Micro LED device.
KAUST believes that with the advantages of high brightness, fast response speed, wide color gamut, and low energy consumption, InGaN Micro LED will be an ideal solution for next-generation Micro LED head-mounted monitors, mobile phones, TVs and other equipment. In the next step, the KAUST team will further improve the efficiency of the Micro LED and reduce the size to less than 10μm.
It is worth noting that Jingneng Optoelectronics has also made breakthroughs on the road to achieve full-color InGaN-based Micro LEDs.
According to LEDinside's understanding, Jingneng Optoelectronics has developed a silicon-based red Micro LED chip and successfully fabricated a GaN-based Micro LED array on a silicon substrate with three primary colors of red, green and blue. However, Jingneng also admitted that the current external quantum efficiency test methods of its red Micro LED chips need to be further optimized.
In terms of the smaller size of Micro LED chip technology, in March this year, the University of California, Santa Barbara (UCSB) has also announced the first demonstration of an InGaN-based red light Micro LED chip with a size of less than 10μm, but it also faces external quantum light emission. The problem of low efficiency. It is reported that the EQE measured on the wafer measurement of this chip is only 0.2%.
UCSB pointed out that the external quantum luminous efficiency of Micro LED must reach at least 2-5% to meet the requirements of terminal displays. UCSB's next plan is to improve material quality and optimize production steps to achieve an increase in external quantum efficiency.
It can be seen that the research teams still have a long way to go in promoting the full-color and commercialization of Micro LEDs. But the good news is that, compared with previous years, the progress made by all parties in Micro LED technology this year has a key role in promoting the Micro LED industry, and terminal products have gradually emerged, which means that manufacturers and consumers are leaving Micro LEDs and A little closer.
