Effect of stacking faults on the photoluminescence spectrum of zincblende GaN

Church, S. A. and Hammersley, S. and Mitchell, P. W. and Kappers, M. J. and Lee, L. Y. and Massabuau, F. and Sahonta, S. L. and Frentrup, M. and Shaw, L. J. and Wallis, D. J. and Humphreys, C. J. and Oliver, R. A. and Binks, D. J. and Dawson, P. (2018) Effect of stacking faults on the photoluminescence spectrum of zincblende GaN. Journal of Applied Physics, 123. 185705. ISSN 0021-8979 (https://doi.org/10.1063/1.5026267)

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Abstract

The photoluminescence spectra of a zincblende GaN epilayer grown via metal-organic chemical vapour deposition upon 3C-SiC/Si (001) substrates were investigated. Of particular interest was a broad emission band centered at 3.4 eV, with a FWHM of 200 meV, which extends above the bandgap of both zincblende and wurtzite GaN. Photoluminescence excitation measurements show that this band is associated with an absorption edge centered at 3.6 eV. Photoluminescence time decays for the band are monoexponential, with lifetimes that reduce from 0.67 ns to 0.15 ns as the recombination energy increases. TEM measurements show no evidence of wurtzite GaN inclusions which are typically used to explain emission in this energy range. However, dense stacking fault bunches are present in the epilayers. A model for the band alignment at the stacking faults was developed to explain this emission band, showing how both electrons and holes can be confined adjacent to stacking faults. Different stacking fault separations can change the carrier confinement energies sufficiently to explain the width of the emission band, and change the carrier wavefunction overlap to account for the variation in decay time.

  • Item type:Article
    ID code:79478
    Dates:
    Date
    Event
    10 May 2018
    Published
    10 May 2018
    Published Online
    23 April 2018
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:04 Feb 2022 11:45
    Last modified:09 Apr 2024 03:00
    URI:https://strathprints.strath.ac.uk/id/eprint/79478
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