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

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2250-2253
Number of pages4
JournalOptics Letters
Issue number9
Publication statusPublished - 2022 May 1

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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