– A step toward realization of high-efficiency, high-resolution micro LED displays –
Researchers: WANG Xuelun, Team Leader, GaN Optical Device Team, GaN Advanced Device Open Innovation Laboratory, ZHU Jun, former Visiting Researcher, Electronics and Photonics Research Institute, ENDO Kazuhiko, Leader, Nanoelectronics Research Institute, and SAMUKAWA Seiji, Joint Appointed Fellow, Nanoelectronics Research Institute, also Tohoku University
- GaN micro LEDs with extremely low processing damage fabricated by using neutral-beam etching
- Emission efficiency at low current densities maintained even when the LED size is reduced to 6 µm
- Expected application to high-efficiency, high-resolution micro LED displays
Current density dependence of the external quantum efficiency of micro LEDs fabricated using (a) conventional inductively coupled plasma etching technology and (b) the neutral-beam etching technology in this research
Micro LED displays that use micro LEDs with a size of approximately 10 µm arranged at high density are recently attracting much attention.
However, the emission efficiency of conventional micro LEDs drops rapidly as the LED size decreases, especially in the low current density region (< 20 A/cm2) that is important for display operation. This has made it a challenge to realize high-efficiency, high-brightness, high-resolution micro LED displays.
The researchers have developed technology for increasing the efficiency of GaN (gallium nitride) micro LEDs, in collaboration with Tohoku University.
Micro LED displays with micro LEDs arranged at high density is expected as high-efficiency, high-brightness, high-resolution displays for next-generation wearable information terminals. However, conventional fabrication methods result in large processing damage on the LED side surfaces, so there was the major issue that the emission efficiency drops significantly when the LED size is reduced. The researchers fabricated GaN micro LEDs using neutral-beam etching technology that is known to have extremely low processing damage, and realized GaN micro LEDs with almost no drop in emission efficiency even when the LED size is reduced to 6 μm.