MicroLED

MicroLEDs (µLEDs) represent the next leap in light emitting diode technology. These minuscule diodes deliver significantly higher brightness and energy efficiency than today’s LEDs, positioning them to disrupt multiple industries. After decades of steady, methodical research, µLED manufacturing is reaching maturity; as it scales, µLEDbased products are expected to outclass their predecessors across the board. Equally important, the technology’s tiny footprint unlocks entirely new categories of devices once thought impossible. Polar Light Technologies, a Swedish µLED startup, is proud to be at the center of this shift.

Polar Light Technologies’ microLEDs

Drawing on years of semiconductor and quantum structure research led by Prof. Per Olof Holtz at Linköping University, we have introduced a novel pyramidal microLED architecture (Fig. 1a). These bottom-up-grown structures, as small as 300 nm, are produced without etching steps. Building on the same approach, we have also developed a proprietary hybrid bonding process that seamlessly marries our LED frontplane to a Si/CMOS backplane (Fig. 1b). One remarkable result of the pyramidal design is a sub-Lambertian, highly focused light lobe (Fig. 1c), ideal for coupling into waveguides and other optical elements.

Our progress accelerated in 2023 with the first blue and green-emitting pyramidal µLEDs; by late 2024 we achieved the industry’s most challenging milestone – red-emitting µLEDs in the same InGaN/GaN material system (Fig. 2). This breakthrough proves that true RGB emission can be fabricated monolithically on a single wafer.

Key Advantages of Polar Light Technologies’ Pyramidal Bottom-Up Process
⦁ Ultrasmall emitters: Demonstrated sub-micron pyramidal LEDs.
⦁ Single-wafer RGB: All three primary colors monolithically on one wafer.
⦁ Optimized optics: Narrow, sub-Lambertian emission enables efficient waveguide coupling.

With these capabilities, Polar Light Technologies is uniquely positioned to deliver monolithic RGB microdisplays – the cornerstone for the next generation of augmented reality (AR) headsets, wearable projectors, and high contrast, ultra-low power screens.

Pyramidal GaN Articles

2022
Son Phuong Le,a) Chih-Wei Hsu, Ivan Martinovic, and Per-Olof Holtz
GaN-based light-emitting materials prepared by hot-wall metal-organic chemical vapor deposition
https://link.springer.com/article/10.1007/s00339-022-05865-7

2021
Son Phuong Le,a) Chih-Wei Hsu, Ivan Martinovic, and Per-Olof Holtz
GaN-based pyramidal quantum structures for micro-size light-emitting diode applications
https://doi.org/10.1063/5.0048684

2015
Tomas Jemsson, Houssaine Machhadani, Per-Olof Hotlz, K Fredrik Karlsson
Polarized single photon emission and photon bunching from an InGaN quantum dot on a GaN micropyramid
https://iopscience.iop.org/article/10.1088/0957-4484/26/6/065702/meta

2014
Anders Lundskog , Chih-Wei Hsu, K Fredrik Karlsson , Supaluck Amloy, Daniel Nilsson1 , Urban Forsberg, Per Olof Holtz1 and Erik Janzen
Direct generation of linearly polarized photon emission with designated orientations from site-controlled InGaN quantum dots
https://www.nature.com/articles/lsa201420

2014
ATomas Jemsson, Houssaine Machhadani, Per-Olof Hotlz, K Fredrik Karlsson, Chih-Wei Hsu
Linearly polarized single photon antibunching from a site-controlled InGaN quantum dot
https://pubs.aip.org/aip/apl/article-abstract/105/8/081901/1077788/Linearly-polarized-single-photon-antibunching-from?redirectedFrom=fulltext

2013
Per Olof Holtz, Chih Wei Hsu, Anders Lundskog, K. Fredrik Karlsson, Urban Forsberg, Erik Janzén
Deterministic Single InGaN Quantum Dots grown on GaN Micro-Pyramid Arrays
https://www.scientific.net/AMR.646.34

2012
Anders Lundskog, Urban Forsberg, Per Olof Holtz and Erik Janzén
Morphology Control of Hot-Wall MOCVD Selective Area Grown Hexagonal GaN Pyramids
https://pubs.acs.org/doi/abs/10.1021/cg301064p

2012
A Lundskog, J Palisaitis, C W Hsu, M Eriksson, K F Karlsson, L Hultman, P O Å Persson, U Forsberg, P O Holtz and E Janzén
InGaN quantum dot formation mechanism on hexagonal GaN/InGaN/GaN pyramids
https://iopscience.iop.org/article/10.1088/0957-4484/23/30/305708/meta

2011
Anders Lundskog, C.W. Hsu, D. Nilsson, K.F. Karlsson, U. Forsberg, P.O. Holtz, E. Janzén
Controlled growth of hexagonal GaN pyramids by hot-wall MOCVD
https://www.sciencedirect.com/science/article/abs/pii/S0022024812008111

2011
Chih-Wei Hsu, Anders Lundskog, K. Fredrik Karlsson, Urban Forsberg, Erik Janz en, and Per Olof Holtz*
Single Excitons in InGaN Quantum Dots on GaN Pyramid Arrays
https://pubs.acs.org/doi/full/10.1021/nl200810v