News: LEDs
23 September 2025
CEA-Leti and CRHEA present step toward full-color AR/VR micro-displays at MicroLED Connect Conference
Micro/nanotechnology R&D center CEA-Leti of Grenoble, France and CNRS–CRHEA (Centre for Research on Heteroepitaxy and its Applications) in Sophia Antipolis, France (which specializes in epitaxial growth of wide-bandgap semiconductor materials) have announced R&D results that have cleared a path toward full-color micro-displays based on a single material system, a long-standing goal for augmented and virtual reality (AR/VR) technologies.
The paper ‘Regular Red-Green-Blue InGaN Quantum Wells With In Content Up To 40% Grown on InGaN Nanopyramids’ is being presented at the MicroLED Connect Conference in Eindhoven, the Netherlands on 24 September.
The project developed a technique for growing high-quality indium gallium nitride (InGaN)-based quantum wells on sub-micron nanopyramids, enabling native emission of red, green and blue (RGB) light from a single material system.
Micro-displays for immersive devices require bright RGB sub-pixels smaller than 10μm x 10μm. “The use of III-nitride materials promises high-efficiency micro-LEDs compared to their organic counterparts,” notes the paper. “However, for such a pixel size, the pick and place process is no longer suitable for combining blue and green micro-LEDs from III-nitrides and red micro-LEDs from phosphide materials on the same platform.” Red-emitting phosphide micro-LEDs also suffer from efficiency losses at small sizes, while color conversion methods face challenges in deposition precision and stability.
The team grew InGaN nanopyramids using metal-organic vapor phase epitaxy (MOVPE) with an epitaxial graphene layer on silicon carbide serving as a selective mask.
“Using these nanostructures relieved the internal strain that usually limits indium incorporation,” says lead author Amélie Dussaigne of CEA-Leti. “As a result, we achieved record indium nitride mole fractions of 40% in the quantum wells — high enough to generate red light reliably without degrading crystal quality,” she adds.
Image: Very regular InGaN-based quantum wells on the nanopyramid sidewals. High indium content (42% and up to 45%), homogeneous red emission. (Images courtesy of CEA-Leti).
“This new technology addresses one of the most difficult bottlenecks in display miniaturization,” says Adrien Michon, a research scientist in the project with CRHEA. “It opens the door to manufacturing full-color micro-displays with unmatched brightness and resolution — critical for next-generation AR and VR.”
Implications for AR/VR displays
The researchers say that the breakthrough enables native RGB emission from a single material system, simplifying integration and improving performance in future micro-displays. Because the nanopyramid structures can be patterned at sub-micron scale, they are well suited for the <10μm pixel pitch demanded by AR/VR headsets, smart glasses and other immersive devices. Longer-term applications include full-color micro-displays for AR/VR, fast optical communications (emission + reception) and, beyond that: photovoltaic applications, and renewable hydrogen production.
www.microledconnect.com/agenda2025
