Increased light extraction from vertical GaN light-emitting diodes with ordered, cone-shaped deep-pillar nanostructures

Ho Myoung An, Jae In Sim, Ki Seob Shin, Yun Mo Sung, Tae Geun Kim

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


In this paper, improved light extraction using cone-shaped deep-pillar nanostructures is demonstrated on the Honeycomb-type vertical GaN light-emitting diodes (VLEDs). In order to produce ordered, cone-shaped deep-pillar patterns on the surface of an n-type GaN, double-layered polystyrene (PS) nanospheres of 500-nm size were coated onto the n-GaN layer by a simple spin-coating. Then, immediately after the O 2 plasma ashing for double-layered PS beads, the Ni metal was deposited and lifted off to form a hard mask for deep pillar etching. Then, the three VLEDsthe reference VLED with no patterns and the two VLEDs with ordered, cone-shaped pillar patterns of 1.0 and 1.5 μ m depth on the n-type GaN surfacewere prepared for comparison. As a result, the output power for the proposed VLEDs with 1.0-and 1.5-μ m-deep cone-shaped patterns has been increased by 200% and 214%, respectively, at 350 mA as compared to the reference VLED. There was a slight sacrifice of operational voltage and leakage current. The improved optical properties are attributed to the multiple scattering of light from the sidewall of the cone-shaped patterns and the increased surface dimension.

Original languageEnglish
Article number6183454
Pages (from-to)891-896
Number of pages6
JournalIEEE Journal of Quantum Electronics
Issue number7
Publication statusPublished - 2012


  • Cone-shaped
  • Double layer coating
  • Gallium nitride
  • Honeycomb-type
  • Nanosphere lithography
  • Vertical light emitting diode

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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