Emission mechanisms of bulk GaN and InGaN quantum wells prepared by lateral epitaxial overgrowth

S. F. Chichibu, H. Marchand, M. S. Minsky, S. Keller, P. T. Fini, J. P. Ibbetson, S. B. Fleischer, J. S. Speck, J. E. Bowers, E. Hu, U. K. Mishra, S. P. DenBaars, T. Deguchi, Takayuki Sota, S. Nakamura

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    Abstract

    The emission mechanisms of bulk GaN and InGaN quantum wells (QWs) were studied by comparing their optical properties as a function of threading dislocation (TD) density, which was controlled by lateral epitaxial overgrowth. Slightly improved excitonic photoluminescence (PL) intensity was recognized by reducing TD density from 1010cm-2 to less than 106cm-2. However, the major PL decay time was independent of the TD density, but was rather sensitive to the interface quality or material purity. These results suggest that TDs simply reduce the net volume of light-emitting area. This effect is less pronounced in InGaN QWs where carriers are effectively localized at certain quantum disk size potential minima to form quantized excitons before being trapped in nonradiative pathways, resulting in a slow decay time. The absence of any change in the optical properties due to reduction of TD density suggested that the effective band gap fluctuation in InGaN QWs is not related to TDs.

    Original languageEnglish
    Pages (from-to)1460-1462
    Number of pages3
    JournalApplied Physics Letters
    Volume74
    Issue number10
    Publication statusPublished - 1999 Mar 8

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    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)

    Cite this

    Chichibu, S. F., Marchand, H., Minsky, M. S., Keller, S., Fini, P. T., Ibbetson, J. P., Fleischer, S. B., Speck, J. S., Bowers, J. E., Hu, E., Mishra, U. K., DenBaars, S. P., Deguchi, T., Sota, T., & Nakamura, S. (1999). Emission mechanisms of bulk GaN and InGaN quantum wells prepared by lateral epitaxial overgrowth. Applied Physics Letters, 74(10), 1460-1462.