Interplay of sidewall damage and light extraction efficiency of micro-LEDs

Jeong Hwan Park; Markus Pristovsek; Wentao Cai; Heajeong Cheong; Takeru Kumabe; Dong Seon Lee; Tae Yeon Seong; Hiroshi Amano

doi:10.1364/OL.456993

Interplay of sidewall damage and light extraction efficiency of micro-LEDs

Jeong Hwan Park, Markus Pristovsek, Wentao Cai, Heajeong Cheong, Takeru Kumabe, Dong Seon Lee, Tae Yeon Seong, Hiroshi Amano

Department of Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm² area µLEDs with various mesa shapes (circular, square, and stripes). Appropriate external quantum efficiency (EQE) can yield internal quantum efficiency (IQE) which decreases with increasing peripheral length of the mesas. However, light extraction efficiency (η_e) increased with increasing mesa periphery. We introduce analysis of J_peak (the current at peak EQE) since it is proportional to the non-radiative recombination. Etching the sidewalls using tetramethylammonium hydroxide (TMAH) increased the peak EQE and decreased the sidewall dependency of J_peak. Quantitatively, the TMAH etching reduced non-radiative surface recombination by a factor of four. Hence, shrinking µLEDs needs an understanding of the relationship between non-radiative recombination and η_e, where analyzing J_peak can offer new insights.

Original language	English
Pages (from-to)	2250-2253
Number of pages	4
Journal	Optics Letters
Volume	47
Issue number	9
DOIs	https://doi.org/10.1364/OL.456993
Publication status	Published - 2022 May 1

ASJC Scopus subject areas

Atomic and Molecular Physics, and Optics

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title = "Interplay of sidewall damage and light extraction efficiency of micro-LEDs",

abstract = "This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm2 area µLEDs with various mesa shapes (circular, square, and stripes). Appropriate external quantum efficiency (EQE) can yield internal quantum efficiency (IQE) which decreases with increasing peripheral length of the mesas. However, light extraction efficiency (ηe) increased with increasing mesa periphery. We introduce analysis of Jpeak (the current at peak EQE) since it is proportional to the non-radiative recombination. Etching the sidewalls using tetramethylammonium hydroxide (TMAH) increased the peak EQE and decreased the sidewall dependency of Jpeak. Quantitatively, the TMAH etching reduced non-radiative surface recombination by a factor of four. Hence, shrinking µLEDs needs an understanding of the relationship between non-radiative recombination and ηe, where analyzing Jpeak can offer new insights.",

author = "Park, {Jeong Hwan} and Markus Pristovsek and Wentao Cai and Heajeong Cheong and Takeru Kumabe and Lee, {Dong Seon} and Seong, {Tae Yeon} and Hiroshi Amano",

note = "Funding Information: National Research Foundation of Korea (NRF-2017K1A1A20 13160). All authors would like to thank Dr. Xue-Lun Wang and Dr. Naoto Kumagai (National Institute of Advanced Industrial Science and Technology) for ITO deposition. Publisher Copyright: {\textcopyright} 2022 Optica Publishing Group",

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T1 - Interplay of sidewall damage and light extraction efficiency of micro-LEDs

AU - Park, Jeong Hwan

AU - Pristovsek, Markus

AU - Cai, Wentao

AU - Cheong, Heajeong

AU - Kumabe, Takeru

AU - Lee, Dong Seon

AU - Seong, Tae Yeon

AU - Amano, Hiroshi

N1 - Funding Information: National Research Foundation of Korea (NRF-2017K1A1A20 13160). All authors would like to thank Dr. Xue-Lun Wang and Dr. Naoto Kumagai (National Institute of Advanced Industrial Science and Technology) for ITO deposition. Publisher Copyright: © 2022 Optica Publishing Group

PY - 2022/5/1

Y1 - 2022/5/1

N2 - This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm2 area µLEDs with various mesa shapes (circular, square, and stripes). Appropriate external quantum efficiency (EQE) can yield internal quantum efficiency (IQE) which decreases with increasing peripheral length of the mesas. However, light extraction efficiency (ηe) increased with increasing mesa periphery. We introduce analysis of Jpeak (the current at peak EQE) since it is proportional to the non-radiative recombination. Etching the sidewalls using tetramethylammonium hydroxide (TMAH) increased the peak EQE and decreased the sidewall dependency of Jpeak. Quantitatively, the TMAH etching reduced non-radiative surface recombination by a factor of four. Hence, shrinking µLEDs needs an understanding of the relationship between non-radiative recombination and ηe, where analyzing Jpeak can offer new insights.

AB - This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm2 area µLEDs with various mesa shapes (circular, square, and stripes). Appropriate external quantum efficiency (EQE) can yield internal quantum efficiency (IQE) which decreases with increasing peripheral length of the mesas. However, light extraction efficiency (ηe) increased with increasing mesa periphery. We introduce analysis of Jpeak (the current at peak EQE) since it is proportional to the non-radiative recombination. Etching the sidewalls using tetramethylammonium hydroxide (TMAH) increased the peak EQE and decreased the sidewall dependency of Jpeak. Quantitatively, the TMAH etching reduced non-radiative surface recombination by a factor of four. Hence, shrinking µLEDs needs an understanding of the relationship between non-radiative recombination and ηe, where analyzing Jpeak can offer new insights.

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SN - 0146-9592

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SP - 2250

EP - 2253

JO - Optics Letters

JF - Optics Letters

IS - 9

ER -

Interplay of sidewall damage and light extraction efficiency of micro-LEDs

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