Improved light output power of GaN-based ultraviolet light-emitting diode using a mesh-type GaN/SiO2/Al omnidirectional reflector

Jun Youn Won, Dae Hyun Kim, Daesung Kang, Jun Suk Sung, Da Som Kim, Sun Kyung Kim, Tae Yeon Seong

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

We investigated the effect of a mesh-type GaN/SiO2/Al omnidirectional reflector (ODR) on the light output power of AlGaN/InGaN-based ultraviolet (365 nm) LEDs and compared their performance with that of LEDs with a GaN/ITO/Al reflector. Using the scattering matrix method, the normal incidence reflectance was calculated to be 93.7% for the GaN/SiO2 (62 nm)/Al ODR and 79% for the GaN/ITO (30 nm)/Al reflector. The Ag/Ni/Al/Ni (52 nm/10 nm/200 nm/20 nm) contact showed a specific contact resistance of 3.2 × 10−5 Ω cm2 after annealing at 500 °C for 1 min. The forward-bias voltages at 20 mA of LEDs with ODR were in the range of 3.49–3.54 V, which were similar to that of LEDs with an ITO/Al reflector (3.51 V). The LEDs with ODR had series resistances in the range of 14.8–12.5 Ω, whereas the LED with an ITO/Al reflector showed 11.7 Ω. The LEDs with ODR yielded 9.3–19.9% higher light output power at 20 mA than the LED with an ITO/Al reflector. The improved light output power was attributed to the optimization of the high reflectance of the ODR (reflective area) and contact area.

Original languageEnglish
Article number1600789
JournalPhysica Status Solidi (A) Applications and Materials Science
Volume214
Issue number8
DOIs
Publication statusPublished - 2017 Aug

Keywords

  • GaN
  • SiO
  • aluminum
  • light extraction
  • light-emitting diodes
  • omnidirectional reflectors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry

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