Modification of carrier localization in basal-plane stacking faults: The effect of Si-doping in a-plane GaN

T. J. Badcock, M. J. Kappers, M. A. Moram, P. Dawson, C. J. Humphreys

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The optical properties of Si-doped a-plane GaN epilayers grown on r-plane sapphire are studied. The low temperature emission is dominated by basal-plane stacking fault (BSF) recombination throughout the investigated doping range (1×10 17 to 5×10 19cm -3). From temperature dependent photoluminescence (PL) measurements in conjunction with PL excitation studies, the carrier localization energy within the BSF is inferred to decrease from 17meV to a negligible level as the doping density increases from 1×10 17 to 5×10 18cm -3. It is proposed that electrons, ionized from the Si-donor atoms at the growth temperature, are able to transfer to the BSFs, where they progressively fill the available density of localized states. For doping levels in excess of 1×10 18cm -3, the luminescence linewidth broadens significantly and the luminescence transients decay with a single exponential time constant. This behaviour is attributed to the onset of band-filling which causes a marked increase in the free electron density within the BSFs.

    Original languageEnglish
    Pages (from-to)498-502
    Number of pages5
    JournalPhysica Status Solidi (B) Basic Research
    Volume249
    Issue number3
    DOIs
    Publication statusPublished - Mar 2012

    Keywords

    • a-plane GaN
    • Basal-plane stacking fault
    • Doping
    • Localization

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