Improved light extraction of nitride-based flip-chip light-emitting diodes by forming air voids on Ar-implanted sapphire substrate

Yu Hsiang Yeh, Jinn-Kong Sheu, Ming Lun Lee, Po Cheng Chen, Yu Chen Yang, Cheng Hsiung Yen, Wei-Chi Lai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

GaN-based flip-chip light emitting diodes (FC-LEDs) with embedded air voids grown on a selective-area Arimplanted AlN/sapphire (AIAS) substrate was demonstrated in this study. The proposed FC LED with an embedded light scattering layer can destroy the light interference and thereby increase the LEE of GaN-based flip-chip LEDs. The epitaxial layers grown on Ar-implanted regions exhibited lower growth rates compared with those grown on implantation-free regions. Accordingly, air voids formed over the implanted regions after merging laterally grown GaN facet fronts. The light-output power of LEDs grown on AIAS was greater than that of LEDs grown on implantation free sapphire substrates. At an injection current of 700 mA, the output power of LEDs grown on AIAS was enhanced by 20% compared with those of LEDs without embedded air voids. The increase in output power was mainly attributed to the scattering of light around the air voids, which increased the probability of photons escaping from the LEDs. This study on FC LEDs with embedded light-scattering layer highlights the potential application of these LEDs as an alternative to conventional patterned sapphire substrates for improving the LEE of GaN/sapphire-based LEDs. Based on ray tracing simulation, if the height and the width of bottom of gaps were increased to 3 μm, the Lop could be enhanced over 60%.

Original languageEnglish
Title of host publicationThirteenth International Conference on Solid State Lighting
EditorsJianzhong Jiao, Matthew H. Kane, Nikolaus Dietz, Jian-Jang Huang
PublisherSPIE
ISBN (Electronic)9781628412178
DOIs
Publication statusPublished - 2014 Jan 1
Event13th International Conference on Solid State Lighting - San Diego, United States
Duration: 2014 Aug 202014 Aug 21

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9190
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

Other13th International Conference on Solid State Lighting
CountryUnited States
CitySan Diego
Period14-08-2014-08-21

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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