Structural effects on highly directional far-field emission patterns of GaN-based micro-cavity light-emitting diodes with photonic crystals

Chun Feng Lai*, Hao-Chung Kuo, Chia Hsin Chao, Peichen Yu, Wen Yung Yeh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

This study theoretically and experimentally investigates the highly directional far-field emission patterns of GaN photonic crystal (PhC) micro-cavity light-emitting diodes (MCLEDs) depending on varying structural parameters. Angular-spectra-resolved electroluminescence measurements reveals the behavior of guided-mode extraction which is significantly affected by the structural parameters of GaN PhC MCLEDs, where the GaN cavity thickness decides the extracted guided mode numbers, PhC lattice constant influences the distribution of far-field emission, and PhC hole depth affects the interaction with guided modes. The proposed GaN ultrathin MCLED (uMCLED) with PhC lattice constant of 420 nm and deep hole depth of 250 nm exhibited a maximum output light extraction efficiency of 248% under one-watt input power compared to GaN non-PhC uMCLED and produced a directional far-field emission pattern at half intensity near ± 17°. The present results indicate that highly directional light extraction enhancement could contribute to developments of many applications, especially for etendue-limited applications such as pico- projectors.

Original languageEnglish
Article number5530327
Pages (from-to)2881-2889
Number of pages9
JournalJournal of Lightwave Technology
Volume28
Issue number19
DOIs
StatePublished - 29 Sep 2010

Keywords

  • GaN
  • light-emitting diodes (LEDs)
  • micro-cavity
  • photonic crystals (PhCs)

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