Light extraction enhancement of InGaN-based green LEDs with a composite omnidirectional reflector

C. H. Lin, H. C. Kuo, C. F. Lai, H. W. Huang, Kok-Ming Leung, C. C. Yu, J. R. Lo

    Research output: Contribution to journalArticle

    Abstract

    We have designed, fabricated and measured the electroluminescence of InGaN-based green light-emitting diodes (LEDs) having composite omni-directional reflectors (ODRs) deposited on their backside. The composite ODR is composed of a stack of two individual ODRs, each of which is made of alternating layers of TiO2 and SiO2 with a thickness ratio that gives the largest possible 1D photonic bandgap. The lattice constants of these individual ODRs are chosen so that the effective bandgap of the resulting ODR completely covers the emission spectrum of the LEDs. The effective bandgap of our ODR extends from 498 nm to 548 nm. At a driving current of 300 mA, and with the LED emission peak at about 525 nm and a FWHM of about 35 nm, the light output powers of the LED with the composite ODR and the LED with a conventional Ti/Al metal reflector are found to be 52.9 mW and 40.7 mW, respectively. This 30% light extraction enhancement can be attributed to our composite ODR which has a higher reflectance, a lower optical absorption and a wider reflection angle compared with the Ti/Al reflector.

    Original languageEnglish (US)
    Article number001
    Pages (from-to)1513-1517
    Number of pages5
    JournalSemiconductor Science and Technology
    Volume21
    Issue number12
    DOIs
    StatePublished - Dec 1 2006

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    reflectors
    Light emitting diodes
    light emitting diodes
    composite materials
    augmentation
    Composite materials
    Energy gap
    Electroluminescence
    Full width at half maximum
    Photonics
    Light absorption
    Lattice constants
    Metals
    thickness ratio
    electroluminescence
    emission spectra
    optical absorption
    photonics
    reflectance
    output

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering
    • Electronic, Optical and Magnetic Materials
    • Materials Science(all)
    • Condensed Matter Physics

    Cite this

    Lin, C. H., Kuo, H. C., Lai, C. F., Huang, H. W., Leung, K-M., Yu, C. C., & Lo, J. R. (2006). Light extraction enhancement of InGaN-based green LEDs with a composite omnidirectional reflector. Semiconductor Science and Technology, 21(12), 1513-1517. [001]. https://doi.org/10.1088/0268-1242/21/12/001

    Light extraction enhancement of InGaN-based green LEDs with a composite omnidirectional reflector. / Lin, C. H.; Kuo, H. C.; Lai, C. F.; Huang, H. W.; Leung, Kok-Ming; Yu, C. C.; Lo, J. R.

    In: Semiconductor Science and Technology, Vol. 21, No. 12, 001, 01.12.2006, p. 1513-1517.

    Research output: Contribution to journalArticle

    Lin, C. H. ; Kuo, H. C. ; Lai, C. F. ; Huang, H. W. ; Leung, Kok-Ming ; Yu, C. C. ; Lo, J. R. / Light extraction enhancement of InGaN-based green LEDs with a composite omnidirectional reflector. In: Semiconductor Science and Technology. 2006 ; Vol. 21, No. 12. pp. 1513-1517.
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