UC Santa Barbara researchers continue to push the boundaries of LED design a little further with a new method that could pave the way toward more efficient and versatile LED display and lighting technology.

UCSB electrical and computer engineering professor Jonathan Schuller and collaborators describe this new approach, which could allow a wide variety of LED devices — from virtual reality headsets to automotive lighting — to become more sophisticated and sleeker at the same time.

(Image: UCSB)

Usually LEDs emit spontaneous light, comparing to laser’s stimulated, coherent light. The research team focused on metasurfaces, the engineered surfaces with nanoscale features that interact with light and manage to control the photons of LED extracting in a desired amount and travel to designated direction.

The design they settled upon consists of an array of 1.45-micrometer long GaN nanorods on a sapphire substrate. Quantum wells of InGaN are embedded in the nanorods to confine electrons and holes and thus emit light. In addition to allowing more light to leave the semiconductor structure, the design polarizes the light, which co-lead author Prasad Iyer said, “is critical for a lot of applications.”

The results were published in Nature Photonics in June 1, 2020. Research on this project also was conducted by Ryan A. DeCrescent (co-lead author), Yahya Mohtashami, Guillaume Lhereux, Nikita Butakov, Abdullah Alhassan, Claude Weisbuch, Shuji Nakamura and Steven P. DenBaars, all from UCSB.