Impact of the surface recombination on InGaN/GaN-based blue micro-light emitting diodes

Jianquan Kou, Chih Chiang Shen, Hua Shao, Jiamang Che, Xu Hou, Chunshuang Chu, Kangkai Tian, Yonghui Zhang, Zi Hui Zhang, Hao-Chung Kuo

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

In this work, the size-dependent effect for InGaN/GaN-based blue micro-light emitting diodes (µLEDs) is numerically investigated. Our results show that the external quantum efficiency (EQE) and the optical power density drop drastically as the device size decreases when sidewall defects are induced. The observations are owing to the higher surface-to-volume ratio for small µLEDs, which makes the Shockley-Read-Hall (SRH) non-radiative recombination at the sidewall defects not negligible. The sidewall defects also severely affect the injection capability for electrons and holes, such that the electrons and holes are captured by sidewall defects for the SRH recombination. Thus, the poor carrier injection shall be deemed as a challenge for achieving high-brightness µLEDs. Our studies also indicate that the sidewall defects form current leakage channels, and this is reflected by the current density-voltage characteristics. However, the improved current spreading effect can be obtained when the chip size decreases. The better current spreading effect takes account for the reduced forward voltage.

Original languageEnglish
Pages (from-to)A643-A653
JournalOptics Express
Volume27
Issue number12
DOIs
StatePublished - 10 Jun 2019

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    Kou, J., Shen, C. C., Shao, H., Che, J., Hou, X., Chu, C., Tian, K., Zhang, Y., Zhang, Z. H., & Kuo, H-C. (2019). Impact of the surface recombination on InGaN/GaN-based blue micro-light emitting diodes. Optics Express, 27(12), A643-A653. https://doi.org/10.1364/OE.27.00A643