Light extraction enhancement with radiation pattern shaping of LEDs by waveguiding nanorods with impedance-matching tips

Yu-Hsuan Hsiao, Cheng-Ying Chen, Li-Chuan Huang, Guan-Jhong Lin, Der-Hsien Lien, Jian-Jang Huang, Jr-Hau He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Syringe-like ZnO nanorods (NRs) were fabricated on InGaN/GaN light emitting diodes (LEDs) by a hydrothermal method. Without sacrificing the electrical performances of LEDs, syringe-like NRs can enhance light extraction capability by 10.5% at 20 mA and shape the radiation profile with a view angle collimated from 136 degrees to 121 degrees. By performing optical experiments and simulation, it is found that the superior light extraction efficiency with a more collimated radiation pattern is attributed to the waveguiding effect of NRs and the mitigation of abrupt index change by the tapered ends of syringe-like ZnO NRs. This work demonstrates the importance of the nanostructure morphology in LED performances and provides the architecture design guidelines of nanostructures to a variety of optical devices.

Original languageEnglish
Pages (from-to)2624-2628
Number of pages5
JournalNanoscale
Volume6
Issue number5
DOIs
StatePublished - Mar 2014

Keywords

  • EMITTING-DIODES
  • SOLAR-CELLS
  • ZNO
  • EFFICIENCY
  • ARRAYS
  • EMISSION
  • SURFACE
  • GROWTH

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