Investigation of sidewall passivation mechanism of InGaN-based blue microscale light-emitting diodes

Kyung Rock Son, Vignesh Murugadoss, Kyeong Heon Kim, Tae Geun Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Microscale light-emitting diodes (µLEDs) have been extensively employed for solid-state lighting applications. However, the ratio of the sidewall area to the emitting area increases as the pixel size of µLEDs decreases, which increases the non-radiative recombination probability on the sidewall surface and eventually degrades the performance of µLEDs. In this study, we investigate the nature of chemical bonds at the sidewall/passivation layer interface using three passivation materials (SiO2, Al2O3, and Si3N4), to identify the underlying mechanism of passivation and thereby achieve high-performance InGaN-based µLEDs. According to the X-ray photoelectron spectroscopy results, the ratio of Ga[sbnd]O bonds on the sidewall/passivation layer interface to Ga[sbnd]N bonds varies with the passivation layer (1.1, 1.06, and 0.33 for SiO2, Al2O3, and Si3N4, respectively). This amount is a key factor affecting the passivation and directly influences the µLED performance. The µLED with SiO2 passivation exhibits a 39% higher light output power and 192% higher current density compared to those associated with the µLED with Si3N4 passivation. These results indicate that the suppression of non-radiative defects depends on the chemical states at the sidewall/passivation layer interface. The findings can provide guidance for optimizing the device performance of µLEDs by selecting appropriate passivation layers.

Original languageEnglish
Article number152612
JournalApplied Surface Science
Volume584
DOIs
Publication statusPublished - 2022 May 15

Keywords

  • Microscale light-emitting diodes
  • Non-radiative recombination
  • Passivation layer
  • Photoluminescence
  • Sidewall defects

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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