Nanomaterials (Jun 2019)

Performance-Enhanced 365 nm UV LEDs with Electrochemically Etched Nanoporous AlGaN Distributed Bragg Reflectors

  • Xingdong Lu,
  • Jing Li,
  • Kang Su,
  • Chang Ge,
  • Zhicong Li,
  • Teng Zhan,
  • Guohong Wang,
  • Jinmin Li

DOI
https://doi.org/10.3390/nano9060862
Journal volume & issue
Vol. 9, no. 6
p. 862

Abstract

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A 365-nm UV LED was fabricated based on embedded nanoporous AlGaN distributed Bragg reflectors (DBR) by electrochemical etching. The porous DBR had a reflectance of 93.5% at the central wavelength of 365 nm; this is the highest value of porous AlGaN DBRs below 370 nm which has been reported so far. An innovative two-step etching method with a SiO2 sidewall protection layer (SPL) was proposed to protect the n-AlGaN layer and active region of UV LED from being etched by the electrolyte. The DBR-LED with SPL showed 54.3% improvement of maximal external quantum efficiency (EQE) and 65.7% enhancement of optical power at 100 mA without any degeneration in electrical properties, compared with the un-etched standard LED sample. This work has paved the way for the application of electrically-pumped UV LEDs and VCSELs based on nanoporous AlGaN DBRs.

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