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Defect-related photoluminescence and photoluminescence excitation as a method to study the excitonic bandgap of AlN epitaxial layers : Experimental and ab initio analysis

Kaminska, Agata ; Koronski, Kamil ; Strak, Pawel ; Wierzbicka, Aleksandra ; Sobanska, Marta ; Klosek, Kamil ; Nechaev, Dmitrii V. ; Pankratov, Vladimir ; Chernenko, Kirill LU and Krukowski, Stanislaw , et al. (2020) In Applied Physics Letters 117(23).
Abstract

We report defect-related photoluminescence (PL) and its vacuum ultraviolet photoluminescence excitation (PLE) spectra of aluminum nitride layers with various layer thicknesses and dislocation densities grown on two different substrates: sapphire and silicon. The defect-related transitions have been distinguished and examined in the emission and excitation spectra investigated under synchrotron radiation. The broad PL bands of two defect levels in the AlN were detected at around 3 eV and 4 eV. In the PLE spectra of these bands, a sharp excitonic peak originating most probably from the A-exciton of AlN was clearly visible. Taking into account the exciton binding energy, the measurements allow determination of the bandgaps of the... (More)

We report defect-related photoluminescence (PL) and its vacuum ultraviolet photoluminescence excitation (PLE) spectra of aluminum nitride layers with various layer thicknesses and dislocation densities grown on two different substrates: sapphire and silicon. The defect-related transitions have been distinguished and examined in the emission and excitation spectra investigated under synchrotron radiation. The broad PL bands of two defect levels in the AlN were detected at around 3 eV and 4 eV. In the PLE spectra of these bands, a sharp excitonic peak originating most probably from the A-exciton of AlN was clearly visible. Taking into account the exciton binding energy, the measurements allow determination of the bandgaps of the investigated AlN samples and their temperature dependencies. Next, they are compared with the literature data obtained by other experimental techniques for bulk AlN crystals and layers grown on different substrates. The obtained results revealed that the AlN bandgap depends on the substrate. The theoretical analysis using density functional theory calculations showed that the effect is induced by the tetragonal strain related to the lattice mismatch between the substrate and the AlN layer, which has a strong influence on the spectral positions of the intrinsic excitons, and consequently on the bandgap of AlN layers.

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publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics Letters
volume
117
issue
23
article number
232101
publisher
American Institute of Physics (AIP)
external identifiers
  • scopus:85097806087
ISSN
0003-6951
DOI
10.1063/5.0027743
language
English
LU publication?
yes
id
9419a677-5c4c-404d-8a82-6ffe623ca446
date added to LUP
2021-01-05 13:51:03
date last changed
2022-04-19 03:12:07
@article{9419a677-5c4c-404d-8a82-6ffe623ca446,
  abstract     = {{<p>We report defect-related photoluminescence (PL) and its vacuum ultraviolet photoluminescence excitation (PLE) spectra of aluminum nitride layers with various layer thicknesses and dislocation densities grown on two different substrates: sapphire and silicon. The defect-related transitions have been distinguished and examined in the emission and excitation spectra investigated under synchrotron radiation. The broad PL bands of two defect levels in the AlN were detected at around 3 eV and 4 eV. In the PLE spectra of these bands, a sharp excitonic peak originating most probably from the A-exciton of AlN was clearly visible. Taking into account the exciton binding energy, the measurements allow determination of the bandgaps of the investigated AlN samples and their temperature dependencies. Next, they are compared with the literature data obtained by other experimental techniques for bulk AlN crystals and layers grown on different substrates. The obtained results revealed that the AlN bandgap depends on the substrate. The theoretical analysis using density functional theory calculations showed that the effect is induced by the tetragonal strain related to the lattice mismatch between the substrate and the AlN layer, which has a strong influence on the spectral positions of the intrinsic excitons, and consequently on the bandgap of AlN layers. </p>}},
  author       = {{Kaminska, Agata and Koronski, Kamil and Strak, Pawel and Wierzbicka, Aleksandra and Sobanska, Marta and Klosek, Kamil and Nechaev, Dmitrii V. and Pankratov, Vladimir and Chernenko, Kirill and Krukowski, Stanislaw and Zytkiewicz, Zbigniew R.}},
  issn         = {{0003-6951}},
  language     = {{eng}},
  number       = {{23}},
  publisher    = {{American Institute of Physics (AIP)}},
  series       = {{Applied Physics Letters}},
  title        = {{Defect-related photoluminescence and photoluminescence excitation as a method to study the excitonic bandgap of AlN epitaxial layers : Experimental and ab initio analysis}},
  url          = {{http://dx.doi.org/10.1063/5.0027743}},
  doi          = {{10.1063/5.0027743}},
  volume       = {{117}},
  year         = {{2020}},
}