Near-Complete Elimination of Size-Dependent Efficiency Decrease in GaN Micro-Light-Emitting Diodes

Jun Zhu, Tokio Takahashi, Daisuke Ohori, Kazuhiko Endo, Seiji Samukawa, Mitsuaki Shimizu, Xue Lun Wang

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Herein, a successful elimination of the size-dependent efficiency decrease in GaN micro-light-emitting diodes (micro-LEDs) is achieved using damage-free neutral beam etching (NBE). The NBE technique, which can obtain ultralow-damage etching of GaN materials, is used in place of the conventional inductively coupled plasma to form the micro-LED mesa. It is found that all the fabricated micro-LEDs with sizes ranging from 40 to 6 μm show external quantum efficiency (EQE) versus current density characteristics similar to those of large-area GaN LEDs, with a maximum in EQE curves at a current density of as low as about 5 A cm−2. Furthermore, all the fabricated micro-LEDs, even the 6 μm one, show a similar value of maximum EQE with a variation of less than 10%, clearly indicating a negligible size dependence of emission efficiency of micro-LEDs fabricated by the NBE technique at least down to the size of 6 μm. These results suggest that the NBE process is a promising method of fabricating high-efficiency sub-10 μm GaN micro-LEDs required for high-efficiency, high-brightness, and high-resolution micro-LED displays.

Original languageEnglish
Article number1900380
JournalPhysica Status Solidi (A) Applications and Materials Science
Issue number22
Publication statusPublished - 2019 Nov 1


  • GaN
  • efficiencies
  • micro-light-emitting diodes
  • neutral beam etching

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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