Bridging the "green gap" of LEDs : Giant light output enhancement and directional control of LEDs via embedded nano-void photonic crystals

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

20 Scopus Citations
View graph of relations

Author(s)

  • Yu-Lin Tsai
  • Che-Yu Liu
  • Chirenjeevi Krishnan
  • Da-Wei Lin
  • You-Chen Chu
  • Tzu-Pei Chen
  • Tien-Lin Shen
  • Tsung-Sheng Kao
  • Martin D. B. Charlton
  • Peichen Yu
  • Chien-Chung Lin
  • Hao-Chung Kuo

Detail(s)

Original languageEnglish
Pages (from-to)1192-1199
Journal / PublicationNanoscale
Volume8
Issue number2
Online published23 Nov 2015
Publication statusPublished - 14 Jan 2016
Externally publishedYes

Abstract

Green LEDs do not show the same level of performance as their blue and red cousins, greatly hindering the solid-state lighting development, which is the so-called "green gap". In this work, nano-void photonic crystals (NVPCs) were fabricated to embed within the GaN/InGaN green LEDs by using epitaxial lateral overgrowth (ELO) and nano-sphere lithography techniques. The NVPCs act as an efficient scattering back-reflector to outcouple the guided and downward photons, which not only boost the light extraction efficiency of LEDs with an enhancement of 78% but also collimate the view angle of LEDs from 131.5° to 114.0°. This could be because of the highly scattering nature of NVPCs which reduce the interference giving rise to Fabry-Perot resonance. Moreover, due to the threading dislocation suppression and strain relief by the NVPCs, the internal quantum efficiency was increased by 25% and droop behavior was reduced from 37.4% to 25.9%. The enhancement of light output power can be achieved as high as 151% at a driving current of 350 mA. Giant light output enhancement and directional control via NVPCs point the way towards a promising avenue of solid-state lighting.

Citation Format(s)

Bridging the "green gap" of LEDs : Giant light output enhancement and directional control of LEDs via embedded nano-void photonic crystals. / Tsai, Yu-Lin; Liu, Che-Yu; Krishnan, Chirenjeevi; Lin, Da-Wei; Chu, You-Chen; Chen, Tzu-Pei; Shen, Tien-Lin; Kao, Tsung-Sheng; Charlton, Martin D. B.; Yu, Peichen; Lin, Chien-Chung; Kuo, Hao-Chung; He, Jr-Hau.

In: Nanoscale, Vol. 8, No. 2, 14.01.2016, p. 1192-1199.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review