The Hunan University team teamed up with Novi, Jingneng and others to develop ultra-high-brightness Micro LED microdisplay chips
Recently, the team of Professor Pan Anlian and Professor Li Dong of Hunan University, together with collaborators such as Novi Technology and Jingneng Optoelectronics, successfully developed an IC-level GaN-based Micro that includes a large-size and high-quality silicon-based Micro LED epitaxial wafer preparation process, non-aligned bonding integration technology and atomic-level sidewall passivation technology. LED wafer manufacturing technology has realized the green Micro LED microdisplay module with the highest brightness reported so far on silicon substrate GaN epitaxial wafers.
Image source: Light:Science & Applications
Relevant research results were published in Light:Science &am titled "Ultra-highbrightness Micro-LEDs with wafer-scale uniform GaN-on-siliconpilayers"p; Published on Applications.
A Korean scientific research team develops new technologies to manufacture high-efficiency submicron Micro LEDs
Foreign media reported that a research team at Kookmin University in South Korea led by Professor Young Rag Do has developed a new top-down process for manufacturing and isolating submicron gallium nitride Micro LEDs. This process combines electrochemical etching and ultrasonic chemical separation techniques to etch porous layers to isolate Micro LEDs.
Image source: Kookmin University, Korea
The researchers used this process to produce gold-coated gallium nitride blue LEDs with an external quantum efficiency (EQE) of 6.21% (at 4.0 V) and a luminous efficiency of 1070 cd/m^2 (at 10.0 V voltage). The diameter of these LEDs is 750 nanometers.
In addition, the researchers further studied the electrochemical variables that affect the nanopore size, separation rate and emission characteristics of dot-shaped LEDs, as well as the impact of solvent type on ultrasonic separation using sonochemical processes.
This research demonstrates the potential of fabricating Micro LEDs through a top-down process, which may be important in improving the performance of Micro LED displays and reducing manufacturing costs. By optimizing electrochemistryand ultrasonic chemical processes, researchers are able to improve the assembly yield and performance of Micro LEDs, providing a new direction for the future development of Micro LED display technology.
The Korean scientific research team used vertical self-assembly process to improve the performance of Micro LED
According to reports, Kookmin University of Korea and Kyung Hee University collaborated to successfully improve the performance of Micro LED through a fluid self-assembly method based on chemical linker chelate bonds. Research shows that compared with previous methods, the assembly efficiency increased by 61.8%. The research team's vertically assembled 1.3-micron Micro LED achieved a peak external quantum efficiency (EQE) of 8.1% and a brightness of 22,300 nits at 9V.
It is reported that researchers have developed a new method to achieve surface-selective vertical assembly of Micro LEDs using chemical connectors that can interact with metal chelating coordination within zinc metal complexes.
Image source: Kookmin University, Korea
The new process is divided into three steps. First, the p-GaN surface of the Micro LED and the bottom Au layer were treated with glycine-thiol using the self-assembled monolayer (SAM) method. In the second step, the glycine-thiol-treated bottom Au electrode is treated with various zinc precursors,To form metal chelate coordination bonds. Finally, the glycine-thiol-treated Micro LED achieves vertical self-assembly through chelate bonds.
A U.S. university team develops high-performance solution-processed transistors for Micro LED displays
It is reported that recently, researchers at the University of Illinois at Urbana-Champaign have developed a new process for manufacturing transistors for high-performance Micro LED displays. The researchers say this is the highest-performing solution-processed semiconductor transistor to date, and it is cheaper.
Image source: University of Illinois
This new process is based on the ordered defect compound semiconductor CuIn5Se8 and is prepared by solution deposition. These transistors are used to form high-speed logic circuits operating at megahertz frequencies to power small 508 PPI blue Micro LED displays.
American and Polish research teams develop the world's first dual electronic chip with transistors and LEDs
It is reported that researchers from Cornell University and the Polish Academy of Sciences collaborated to develop the world's first chip that combines LEDs and transistors. This dual electronic chip may provide new ideas for realizing smaller, lower-cost, and more efficient LEDs.
Image source: Cornell University
Specifically, the researchers built the gallium nitride device to have a high electron mobility transistor (HEMT) on one side and an LED on the other side. The researchers took advantage of gallium nitride's unique property of having large electron polarization along the crystallographic axis, giving each surface different physical and chemical properties. The gallium side is suitable for photonic devices, while the nitrogen side is suitable for transistor devices.
The researchers first grew a transparent gallium nitride substrate (400 microns thick) on a single wafer, and then used molecular beam epitaxy (MBE) technology to grow HEMT and LED heterostructures. The device was shipped to Cornell University, which continues to build and process the HEMT on the nitrogen electrode surface. The final step is to create the LED on the metal side, using a thick positive photoresist coating to protect the previously processed n-side.
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