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Effect of stacking faults on the photoluminescence spectrum of zincblende GaN

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Church, SA 
Hammersley, S 
Mitchell, PW 
Kappers, MJ 
Lee, LY 

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.

Description

Keywords

51 Physical Sciences, 40 Engineering, 4018 Nanotechnology

Journal Title

Journal of Applied Physics

Conference Name

Journal ISSN

0021-8979
1089-7550

Volume Title

123

Publisher

AIP Publishing
Sponsorship
Engineering and Physical Sciences Research Council (EP/M010589/1)
Engineering and Physical Sciences Research Council (EP/N01202X/1)
Engineering and Physical Sciences Research Council (EP/R01146X/1)
Engineering and Physical Sciences Research Council (EP/P03036X/1)
This was work funded by EPSRC under Grant Nos. EP/M010627/1 and EP/N01202X/1, and Innovate UK under Grant No. 56917-383420.
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