Reducing efficiency droop in (In,Ga)N/Gan light-emitting diodes by improving current spreading with electron-blocking layers of the same size as the N-pad

Quoc Hung Pham, Jyh Chen Chen, Huy Bich Nguyen

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

In this study, the traditional electron-blocking layer (EBL) in (In,Ga)N/GaN light-emitting diodes is replaced by a circular EBL that is the same size as the n-pad. The three-dimensional (3D) nonlinear Poisson, drift-diffusion, and continuity equations are adopted to simulate current transport in the LED and its characteristics. The results indicate that the local carrier-density distribution obtained for the circular EBL design is more uniform than that for the traditional EBL design. This improves the uniformity of local radiative recombination and local internal quantum efficiency (IQE) at high injection levels, which leads to a higher lumped IQE and lower efficiency droop. With the circular EBL, the lumped IQE is higher in the outer active region and lower in the active region under the n-pad. Since most emissions from the active region under the n-pad are absorbed by the n-pad, obviously, an LED with a circular EBL will have a higher external quantum efficiency (EQE). The results also show that this LED works at lower applied voltages.

Original languageEnglish
Pages (from-to)380-390
Number of pages11
JournalCurrent Optics and Photonics
Volume4
Issue number4
DOIs
StatePublished - 2020

Keywords

  • Current crowding
  • Efficiency droop
  • Electron blocking layer OCIS codes: (230.3670) Light-emitting diodes; (160.6000) Semiconductor materials
  • Light-emitting diodes

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