Impact of internal electric field and localization effect on quantum well excitons in AlGaN/GaN/InGaN light emitting diodes

S. F. Chichibu, Takayuki Sota, K. Wada, O. Brandt, K. H. Ploog, S. P. DenBaars, S. Nakamura

    Research output: Contribution to journalArticle

    72 Citations (Scopus)

    Abstract

    Strained InxGa1-xN quantum wells (QWs) on thick GaN base layers were investigated to verify the importance of localized QW excitons in their spontaneous emission mechanisms. A strength of the internal piezoelectric field (FPZ) across the QW increases with increasing x up to 1.4 MV/cm for x = 0.25, since the in-plain strain increases. For the QWs with the well thickness L greater than 3 nm, FPZ dominates the emission peak energy due to the quantum-confined Stark effect. Absorption spectra of both hexagonal and cubic InGaN QWs exhibited a broad band-tail regardless of the presence of FPZ normal to the QW plane. The luminescence peak energy of the 3 nm thick QWs was higher than the bandgap energy of the unstrained bulk crystal for x < 0.15, showing that doping of Si in barriers or injection of carriers effectively screens the field. The emission lifetime increased with increasing monitoring wavelength. Also, a temperature-induced change in the luminescence peak energy decreased with increasing x. The real-space variation of the luminescence peak energy was confirmed by the spatially-resolved monochromatic cathodoluminescence mapping method. The localization depth increases with increasing x. The carrier localization is confirmed to originate from the effective bandgap inhomogeneity due to a fluctuation of the local InN mole fraction, which is enhanced by the large and composition-dependent bowing parameter of InGaN material.

    Original languageEnglish
    Pages (from-to)91-98
    Number of pages8
    JournalPhysica Status Solidi (A) Applied Research
    Volume183
    Issue number1
    DOIs
    Publication statusPublished - 2001 Jan

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    Excitons
    Semiconductor quantum wells
    Light emitting diodes
    light emitting diodes
    Electric fields
    excitons
    quantum wells
    electric fields
    Luminescence
    luminescence
    Energy gap
    energy
    Stark effect
    Bending (forming)
    Cathodoluminescence
    Spontaneous emission
    aluminum gallium nitride
    LDS 751
    cathodoluminescence
    plains

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

    Cite this

    Impact of internal electric field and localization effect on quantum well excitons in AlGaN/GaN/InGaN light emitting diodes. / Chichibu, S. F.; Sota, Takayuki; Wada, K.; Brandt, O.; Ploog, K. H.; DenBaars, S. P.; Nakamura, S.

    In: Physica Status Solidi (A) Applied Research, Vol. 183, No. 1, 01.2001, p. 91-98.

    Research output: Contribution to journalArticle

    Chichibu, S. F. ; Sota, Takayuki ; Wada, K. ; Brandt, O. ; Ploog, K. H. ; DenBaars, S. P. ; Nakamura, S. / Impact of internal electric field and localization effect on quantum well excitons in AlGaN/GaN/InGaN light emitting diodes. In: Physica Status Solidi (A) Applied Research. 2001 ; Vol. 183, No. 1. pp. 91-98.
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    AU - Sota, Takayuki

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    AU - Ploog, K. H.

    AU - DenBaars, S. P.

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