Surface lattice resonances for beaming and outcoupling green mu LEDs emission

Light-Emitting Diodes (LEDs) exhibit a typical Lambertian emission, raising the need for secondary optics to tailor their emission depending on specific applications. Here, we introduce plasmonicmetasurfaces to InGaN green emitting quantum wells for LEDs to control their far-field emission directionality and enhance the collection efficiency. The proposed mechanism is based on surface lattice resonances (SLRs) and relies on the near-field coupling between the InGaN multiple quantum wells (MQWs) and periodic arrays of aluminum (Al) nanodisks. Fourier microscopy measurements reveal that the angular photoluminescence emission pattern depends on the lattice constant of the metasurfaces. We demonstrate that integrating Al metasurfaces in LED wafers can enhance the collected outcoupled light intensity by a factor of 5 compared to the same sample without metasurfaces. We have also performed numerical calculations of the far-field emission based on the reciprocity principle and obtained a very good agreement with the experimental data. The proposed approach controls the emission directionality without the need for secondary optics and it does not require postetching of the GaN, which makes it a potential candidate to control and enhance the generated light from micro-LEDs.

Automated summary

This study introduces the use of plasmonic metasurfaces to control the emission directionality and enhance the collection efficiency of LEDs. The proposed mechanism relies on the near-field coupling between quantum wells and periodic arrays of aluminum nanodisks. Experimental results show that integrating metasurfaces in LED wafers can increase the collected outcoupled light intensity by a factor of 5. The proposed approach does not require secondary optics or postetching of GaN, making it a potential candidate for enhancing light emission from micro-LEDs.