The dependence of light extraction improvement on optimized surface microstructure for AlGaN-based UVC-LEDs considering TM-polarized emission

The dependence of light extraction improvement on optimized surface microstructure for AlGaN-based UVC-LEDs considering TM-polarized emission

Zhu, Yifan (University of Science and Technology Beijing)
Lu, Huimin (University of Science and Technology Beijing)
Wang, Jianping (University of Science and Technology Beijing)
Yu, Tongjun (Peking University)
Li, Z.Z.L. (TU Delft ImPhys/Esmaeil Zadeh group)
Tian, Yucheng (Peking University)

2023

In order to improve the light extraction of AlGaN-based short wavelength ultraviolet light emitting diodes (DUC-LEDs), a type of microstructure with high aspect ratio is introduced and optimized on the AlN substrate surface. And, particle swarm optimization (PSO) algorithm is used to inverse design of the surface microstructure to maximize the light extraction efficiency (LEE). Considering that the propagation characteristics of TM-polarized light are different from that of TE-polarized light, the optical field distribution and LEE is analyzed for the UVC-LEDs with different TE-polarized component when the optimized surface microstructure is applied. Furthermore, the preparation process tolerance of the high aspect ratio structure is discussed by calculating the LED's LEE when the structural deviation occurs or morphology changes. Simulation results show that, by using the optimized surface microstructure based on parabola cone array, the LEDs' LEE is increased from 4.4% to 8.7% and from 0.4% to 3.7% for TE-polarized and TM-polarized emission, respectively. In addition, it is demonstrated that the light extraction improvement by the surface microstructure has a good tolerance to the structural deviation and morphology. The results are significant for improving light extraction and realizing high efficient short wavelength AlGaN-based UVC-LEDs by designing surface microstructures.

Light extraction efficiency
Polarized component
Ultraviolet light emitting diodes

http://resolver.tudelft.nl/uuid:e4ed771f-b526-4f52-9082-4831fbeea3ce

https://doi.org/10.1016/j.micrna.2023.207614

2023-11-24

Micro and Nanostructures, 181

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Yifan Zhu, Huimin Lu, Jianping Wang, Tongjun Yu, Z.Z.L. Li, Yucheng Tian