Single-step-fabricated disordered metasurfaces for enhanced light extraction from LEDs

Peng Mao, Changxu Liu*, Mengxia Liu, Xiyan Li, Qiang Chen, Min Han, Stefan Maier, Edward Sargent*, Shuang Zhang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

While total internal reflection (TIR) lays the foundation for many important applications, foremost fibre optics that revolutionised information technologies, it is undesirable in some other applications such as light-emitting diodes (LEDs), which are a backbone for energy-efficient light sources. In the case of LEDs, TIR prevents photons from escaping the constituent high-index materials. Advances in material science have led to good efficiencies in generating photons from electron–hole pairs, making light extraction the bottleneck of the overall efficiency of LEDs. In recent years, the extraction efficiency has been improved, using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum. However, the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and time-consuming fabrication, which causes a gap between lab demonstration and industrial-level applications. Inspired by lightning bugs, we propose and realise a disordered metasurface for light extraction throughout the visible spectrum, achieved with single-step fabrication. By applying such a cost-effective light extraction layer, we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs, demonstrating a substantial potential for global energy-saving and sustainability.
Original languageEnglish
Article number180
Number of pages9
JournalLight: Science and Applications
Volume10
Issue number1
Early online date6 Sep 2021
DOIs
Publication statusE-pub ahead of print - 6 Sep 2021
Externally publishedYes

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