Polarized edge emission from GaN-based light-emitting diodes sandwiched by dielectric/metal hybrid reflectors

L. J. Yan, J. K. Sheu, F. W. Huang, M. L. Lee

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1 Citation (Scopus)


Edge-emitting c-plane GaN/sapphire-based light-emitting diodes (LEDs) sandwiched by two dielectric/metal hybrid reflectors on both sapphire and GaN surfaces were studied to determine their light emission polarization. The hybrid reflectors comprised dielectric multiple thin films and a metal layer. The metal layers of Au or Ag used in this study were designed to enhance the polarization ratio from S-polarization (transverse electric wave, TE) to P-polarization (transverse magnetic wave, TM). The two sets of optimized dielectric multi thin films served as matching layers for wide-angle incident light on both sapphire and GaN surfaces. To determine which reflector scheme would achieve a higher polarization ratio, simulations of the reflectance at the hybrid reflectors on sapphire (or GaN) interface were performed before the fabrication of experimental LEDs. Compared with conventional c-plane InGaN/GaN/sapphire LEDs without dielectric/metal hybrid reflectors, the experimental LEDs exhibited higher polarization ratio (ITE-max / ITM-max) with r=2.174 (∼3.37 dB) at a wavelength of 460 nm. In contrast, the original polarized light (without dielectric/metal hybrid reflectors) was partially contributed (r=1.398) by C-HH or C-LH (C band to the heavy-hole sub-band or C band to the crystal-field split-off sub-band) transitions along the a -plane or m -plane direction.

Original languageEnglish
Article number113102
JournalJournal of Applied Physics
Issue number11
Publication statusPublished - 2010 Dec 1

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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