Effect of stacking faults on the photoluminescence spectrum of zincblende GaN

Church, S. A., Hammersley, S., Mitchell, P. W., Kappers, M. J., Lee, L. Y., Massabuau, F., Sahonta, S. L., Frentrup, M., Shaw, L. J., Wallis, D. J. ORCID: https://orcid.org/0000-0002-0475-7583, Humphreys, C. J., Oliver, R. A., Binks, D. J. and Dawson, P. 2018. Effect of stacking faults on the photoluminescence spectrum of zincblende GaN. Journal of Applied Physics 123 (18) , 185705. 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
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	AIP Publishing
ISSN:	0021-8979
Date of First Compliant Deposit:	15 May 2018
Date of Acceptance:	23 April 2018
Last Modified:	21 Nov 2024 16:30
URI:	https://orca.cardiff.ac.uk/id/eprint/111386

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