Technical / research

Researchers from Korea's Kookmin University have developed a new GaN-based fin-LED chip material and pixel process technology, saying that this innovation may be the key to overcome the limitations of current microLED technologies.

The researchers developed a viable pixel manufacturing process that vertically assembles sub-micron-sized fin-LEDs using a face-selective dielectrophoresis (DEP) assembly method. The GaN-based sub-micron-sized fin-LEDs are designed to maximize performance while minimizing costs related to the chips and pixelation process. This technology significantly enhances extraction light efficiency by vertically aligning the fin-LEDs, and it enables the implementation of chip materials and pixel manufacturing processes that significantly reduce production costs.

Researchers from the KAIST institute in Korea have developed a microLED-based face mask, that aims to slow down skin aging. The researchers say that the mask's flexibility enables uniform light penetration and so can slow down skin aging. The team conducted trials in collaboration with a university hospital, and found out that skin elasticity in the dermal layer improved by 340% compared to conventional LED masks.

Each light mask has 3,770 microLED devices, and a light diffusion layer that disperses the light evenly. The researchers did not detail the size or properties of the microLEDs. The researchers have licensed the technology to FRONICS that plans to commercialize it. 

Researchers from Korea's Kookmin University in Seoul, led by Prof. Young Rag Do, have developed a novel top-down process to fabricate and isolate sub-micron GaN microLEDs. The process combines electrochemical etching and sonochemical separation of the etched porous layer to isolate the microLEDs.

The researchers have used the process to produce Au-coated GaN blue LEDs that offer an EQE of 6.21% (at 4.0 V) and a luminous efficacy of 1,070 cd/m2 (at 10.0 V). The LEDs themselves had a diameter of 750 nm, these are true sub-micon LEDs.

Finland-Based Comptek Solutions announced that it has successfully designed and installed a pilot line that integrates its Kontrox passivation technology with industry-standard techniques like Atomic Layer Deposition (ALD) for substrates up to 200mm. The company says that its technology minimizes surface defects and ensuring an exceptionally high-quality III-V dielectric interface.

The new facility enables Comptek to deliver scalable solutions for a wide range of applications, including power electronics and optoelectronics. One of the key applications for Comptek are microLED devices. Back in 2022, we posted a spotlight on Comptek and a short interview with its CEO, that highlights how the performance of microLED devices is increased thanks to the passivation technology.

Researchers from Hunan University have designed and grown wafer-scale uniform green GaN epilayer on silicon wafers (4-inch and 6-inch in size). The epilayer was of very high uniformity and showed excellent properties. Using this wafer, the researchers developed green microLED displays reaching over 10 million nits.

This epilayer demonstrated a low dislocation density of 5.25×108 cm^-2, minimal wafer bowing of 16.7 μm, and high wavelength uniformity (STDEV<1 nm). The researcher integrated the Micro-LEDs with CMOS circuits and created 1080x780 monochrome green microLED displays, which offered the ultra high brightness.

Researchers from Korea's Kookmin University in collaboration with colleagues from Kyung Hee University have managed to enhance the performance of microLEDs produced using fluidic self-assembly based on chelation bonds of chemical linkers. The researcher report up to 61.8% increase in assembly yield compared to previous methods, and their vertically assembled 1.3 um microLEDs achieved a peak EQE of 8.1% and a brightness of 22,300 nits at 9 V.

The researcher developed a novel approach for the face-selective vertical assembly of microLEDs using a chemical linker capable of engaging in metal chelate coordination interactions within Zn metal complexes.

Researchers from Cornell University, in collaboration with researchers from the Polish Academy of Science have developed the world's first chip that combines an LED and a transistor. This so-called Dualtronic chip could pave the way towards smaller, lower-cost and more efficient LEDs. 

The researchers built their GaN device so that on one side it has a high electron mobility transistor (HEMT), and on the other side it has an LED. The researchers take advantage of a unique property of GaN - the fact that it has a large electronic polarization along its crystal axis, which gives each of its surfaces dramatically different physical and chemical properties. The gallium side is useful for photonic devices, while the Nitrogen side is useful for transistor devices.

On September 24-26, the inaugural MicroLED-Connect event took place in Eindhoven, The Netherlands. It was an extremely successful event with attendees, speakers and exhibitors from all over the world there to discuss the latest microLED innovations and updates. It is clear that there's much interest and driving force behind the microLED industry.

MicroLED-Connect hosted over 40 speakers and 8 masterclasses, providing a wealth of information by leading display makers and supply chain companies, researchers, material makers, market analysts, investors, application developers, and more. The agenda included speakers from Google, Meta, TCL CSoT, KAUST, JCDecaux, CEA/Leti, GlobalFoundries, Aixtron, Continental, Applied Materials, imec.Xpand, VueReal, ALLOS and many more.

You can now access all of the event recordings (and proceedings), in addition to recordings and presentations from past microLED-Connect virtual events. MicroLED-Connect offers yearly passes to access all of the content, in addition to online access to events during the year.

Researchers from the University of Illinois Urbana-Champaign developed a new process to create transistors for high-performance microLED displays. The researchers say that this is the highest performing solution-processed semiconductor transistor to date, and a potential low-cost one.

The new method is based on ordered defect compound semiconductor CuIn5Se8 prepared by solution deposition. These transistors were used to form high-speed logic circuits operating in megahertz, to power a small 508 PPI blue microLED display (8 micron LEDs).

OTFT developer Smartkem, a MicroLED Industry Association member, announced that it has signed an agreement with Shanghai Chip Foundation Semiconductor Technology to co-develop microLED-based backlight units for LCD displays.

Smartkem prototype microLED display

The new backlight units will use Smartkem's proprietary organic dielectric single layer material, or Redistribution Layer (RDL). Chip Foundatiion will use the material with its own microLED devices. As part of the co-development project, Smartkem will develop specifica insulator materials to be used by Chip Foundation. The project will develop miniLED packages that contain four microLEDs wired in series. Smartkem says that the chip will offer high brightness, high current efficiency, improved uniformity and lower power consumption compared to current miniLED based backlighting units.