Coherent vertical beaming using Bragg mirrors for high-efficiency GaN light-emitting diodes

Sun Kyung Kim, Hong Kyu Park

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We propose a dielectric Bragg mirror that utilizes coherent coupling with multiple quantum wells (MQWs) to significantly enhance light extraction from GaN light-emitting diode (LED). Full vectorial electromagnetic simulation showed that, under constructive interference conditions, the Bragg mirror consisting of two dielectric (SiO2/TiO2) stacks and a silver layer led to >30% enhancement in light extraction, as compared to a single silver mirror. Such significant enhancement by a pre-designed Bragg/metal mirror was ascribed to the vertically oriented radiation pattern and reduced plasmonic metal loss. In addition, the gap distance between the MQWs and a Bragg mirror at which the constructive interference takes place could be controlled by modulating the thickness of the first lowrefractive- index layer. Moreover, a two-dimensional periodic pattern was incorporated into an upper GaN layer with the designed Bragg mirror and it was shown that a lattice constant of ~800 nm was optimal for light extraction. We believe that tailoring the radiation profile of light emitters by coherent coupling with designed high-reflectivity mirrors will be a promising route to overcome the efficiency limit of current semiconductor LED devices.

Original languageEnglish
Pages (from-to)14566-14572
Number of pages7
JournalOptics Express
Volume21
Issue number12
DOIs
Publication statusPublished - 2013 Jun 1

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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