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

This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm 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...

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Bibliographic Details
Published in:Optics letters 2022-05, Vol.47 (9), p.2250-2253
Main Authors: Park, Jeong-Hwan, Pristovsek, Markus, Cai, Wentao, Cheong, Heajeong, Kumabe, Takeru, Lee, Dong-Seon, Seong, Tae-Yeon, Amano, Hiroshi
Format: Article
Language:English
Subjects:
Efficiency
Etching
Impact damage
Light emitting diodes
Mesas
Quantum efficiency
Radiative recombination
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Summary:This Letter describes the impact of shape on micro light-emitting diodes (µLEDs), analyzing 400 µm 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.
ISSN:0146-9592
1539-4794
DOI:10.1364/OL.456993