Improved performance of deep ultraviolet AlGaN-based light-emitting diode by reducing contact resistance of Al-based reflector

Kee Baek Sim, Jun Young Jin, Su Kyung Kim, Young Jin Ko, Gyu Weon Hwang, Tae Yeon Seong, Hiroshi Amano

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In this study, chlorine (Cl) treatment was carried out on p-AlGaN to enhance the performance of ultraviolet-C light emitting diodes (UVC LEDs) by modifying ITO work function and hence reducing the contact resistance of ITO/Al reflector. The Cl-treated UVC LEDs exhibit the forward voltage of 6.88 V at 20 mA, whereas the reference samples show 7.50 V. The light output power and relative wall plug efficiency (WPE) of the Cl-treated UVC LEDs are enhanced by 17.1% at 500 mW and 19.5% at 100 mA, respectively, as compared to the reference. Additionally, the Cl-treated LEDs also display reduction in both the leakage current and ideality factor. Further, the photoluminescence (PL) intensity of AlGaN micro-disks is also enhanced by the Cl-treatment. X-ray photoemission spectroscopy (XPS) results indicate the formation of Cl-ITO at the ITO/p-AlGaN interface and the passivation of the surface states of AlGaN by Cl radicals. Based on the XPS results, a possible mechanism for the improved performance of Cl-treated UVC AlGaN-based LEDs is described and discussed.

Original languageEnglish
Article number164895
JournalJournal of Alloys and Compounds
Publication statusPublished - 2022 Jul 25

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSICT) ( NRF-2017K1A1A2013160 and NRF-2022R1A2C2006887 ), the KIST Institution Program (No. 2E31040 ), and the Institute of Civil Military Technology Cooperation funded by the Defense Acquisition Program Administration .

Publisher Copyright:
© 2022 Elsevier B.V.


  • Chlorine treatment
  • ITO
  • Surface passivation
  • UVC LEDs
  • Work function

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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