A luminescence study of Cu2ZnSnSe4/Mo/glass films and solar cells with near stoichiometric copper content

M. V. Yakushev, M.A. Sulimov, J. Márquez-Prieto, I. Forbes, P.R. Edwards, V.D. Zhivulko, O.M. Borodavchenko, A. V. Mudryi, J. Krustok, R. W. Martin

Research output: Contribution to journalArticle

Abstract

Cu2ZnSnSe4 (CZTSe) is one of the leading candidates for the absorber layer in sustainable solar cells. Thin films of CZTSe with a near stoichiometric [Cu]/[Zn+Sn] were used to produce solar cells with conversion efficiency η = 6.4% by a standard solar cell processing including KCN etching and the deposition of CdS and ZnO. Both CZTSe films and solar cells were examined using photoluminescence (PL) to analyse the nature of radiative recombination and photoluminescence excitation (PLE) at 4.2 K to determine the bandgap (Eg). Low temperature PL spectra of the films reveal an intense band P1 at 0.81 eV and a low intensity band P2 at 0.93 eV. Their temperature and excitation intensity dependencies suggest that they both involve recombinations of free electrons with holes localised at acceptors with the energy level influenced by potential fluctuations in the valence band . We associate P1 and P2 with different fractions of CZTSe: with a lower and higher degree of order of Cu and Zn on the cati on sub-lattice, respectively. Device processing reduced the intensity of P1 by 2.5 whereas the intensity of P2 increased by a 1.5. We assign this to a low temperature annealing due to CdS and ZnO deposition which increased the fraction of CZTSe with high d egree of Cu/Zn order and decreased the fraction with low degree of Cu/Zn order. Device processing increased Eg, blue shifted P1, decreased its width, j-shift and the mean depth of potential fluctuations. These can also be related to the annealing and/or KCN etching and the chemical effect of Cd, due to CdS replacing copper at the CdS - CZTSe interface layer. Processing induced a new broad band P3 at 1.3 eV (quenching with Ea = 200 meV) which we attributed to defects in the CdS layer.
LanguageEnglish
Article number055502
Number of pages10
JournalJournal of Physics D: Applied Physics
Volume52
Issue number5
Early online date28 Nov 2018
DOIs
Publication statusPublished - 30 Jan 2019

Fingerprint

Luminescence
Copper
Solar cells
solar cells
luminescence
Glass
copper
Photoluminescence
glass
Processing
cells
photoluminescence
Etching
etching
Annealing
annealing
chemical effects
radiative recombination
Valence bands
Temperature

Keywords

  • solar cells
  • photoluminescence
  • CZTSe

Cite this

Yakushev, M. V. ; Sulimov, M.A. ; Márquez-Prieto, J. ; Forbes, I. ; Edwards, P.R. ; Zhivulko, V.D. ; Borodavchenko, O.M. ; Mudryi, A. V. ; Krustok, J. ; Martin, R. W. / A luminescence study of Cu2ZnSnSe4/Mo/glass films and solar cells with near stoichiometric copper content. In: Journal of Physics D: Applied Physics. 2019 ; Vol. 52, No. 5.
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Yakushev, MV, Sulimov, MA, Márquez-Prieto, J, Forbes, I, Edwards, PR, Zhivulko, VD, Borodavchenko, OM, Mudryi, AV, Krustok, J & Martin, RW 2019, 'A luminescence study of Cu2ZnSnSe4/Mo/glass films and solar cells with near stoichiometric copper content' Journal of Physics D: Applied Physics, vol. 52, no. 5, 055502. https://doi.org/10.1088/1361-6463/aaefe3

A luminescence study of Cu2ZnSnSe4/Mo/glass films and solar cells with near stoichiometric copper content. / Yakushev, M. V.; Sulimov, M.A.; Márquez-Prieto, J.; Forbes, I.; Edwards, P.R.; Zhivulko, V.D.; Borodavchenko, O.M.; Mudryi, A. V.; Krustok, J.; Martin, R. W.

In: Journal of Physics D: Applied Physics, Vol. 52, No. 5, 055502, 30.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A luminescence study of Cu2ZnSnSe4/Mo/glass films and solar cells with near stoichiometric copper content

AU - Yakushev, M. V.

AU - Sulimov, M.A.

AU - Márquez-Prieto, J.

AU - Forbes, I.

AU - Edwards, P.R.

AU - Zhivulko, V.D.

AU - Borodavchenko, O.M.

AU - Mudryi, A. V.

AU - Krustok, J.

AU - Martin, R. W.

N1 - This is an author-created, un-copyedited version of an article accepted for publication in Journal of Physics D: Applied Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://iopscience.iop.org/journal/0022-3727.

PY - 2019/1/30

Y1 - 2019/1/30

N2 - Cu2ZnSnSe4 (CZTSe) is one of the leading candidates for the absorber layer in sustainable solar cells. Thin films of CZTSe with a near stoichiometric [Cu]/[Zn+Sn] were used to produce solar cells with conversion efficiency η = 6.4% by a standard solar cell processing including KCN etching and the deposition of CdS and ZnO. Both CZTSe films and solar cells were examined using photoluminescence (PL) to analyse the nature of radiative recombination and photoluminescence excitation (PLE) at 4.2 K to determine the bandgap (Eg). Low temperature PL spectra of the films reveal an intense band P1 at 0.81 eV and a low intensity band P2 at 0.93 eV. Their temperature and excitation intensity dependencies suggest that they both involve recombinations of free electrons with holes localised at acceptors with the energy level influenced by potential fluctuations in the valence band . We associate P1 and P2 with different fractions of CZTSe: with a lower and higher degree of order of Cu and Zn on the cati on sub-lattice, respectively. Device processing reduced the intensity of P1 by 2.5 whereas the intensity of P2 increased by a 1.5. We assign this to a low temperature annealing due to CdS and ZnO deposition which increased the fraction of CZTSe with high d egree of Cu/Zn order and decreased the fraction with low degree of Cu/Zn order. Device processing increased Eg, blue shifted P1, decreased its width, j-shift and the mean depth of potential fluctuations. These can also be related to the annealing and/or KCN etching and the chemical effect of Cd, due to CdS replacing copper at the CdS - CZTSe interface layer. Processing induced a new broad band P3 at 1.3 eV (quenching with Ea = 200 meV) which we attributed to defects in the CdS layer.

AB - Cu2ZnSnSe4 (CZTSe) is one of the leading candidates for the absorber layer in sustainable solar cells. Thin films of CZTSe with a near stoichiometric [Cu]/[Zn+Sn] were used to produce solar cells with conversion efficiency η = 6.4% by a standard solar cell processing including KCN etching and the deposition of CdS and ZnO. Both CZTSe films and solar cells were examined using photoluminescence (PL) to analyse the nature of radiative recombination and photoluminescence excitation (PLE) at 4.2 K to determine the bandgap (Eg). Low temperature PL spectra of the films reveal an intense band P1 at 0.81 eV and a low intensity band P2 at 0.93 eV. Their temperature and excitation intensity dependencies suggest that they both involve recombinations of free electrons with holes localised at acceptors with the energy level influenced by potential fluctuations in the valence band . We associate P1 and P2 with different fractions of CZTSe: with a lower and higher degree of order of Cu and Zn on the cati on sub-lattice, respectively. Device processing reduced the intensity of P1 by 2.5 whereas the intensity of P2 increased by a 1.5. We assign this to a low temperature annealing due to CdS and ZnO deposition which increased the fraction of CZTSe with high d egree of Cu/Zn order and decreased the fraction with low degree of Cu/Zn order. Device processing increased Eg, blue shifted P1, decreased its width, j-shift and the mean depth of potential fluctuations. These can also be related to the annealing and/or KCN etching and the chemical effect of Cd, due to CdS replacing copper at the CdS - CZTSe interface layer. Processing induced a new broad band P3 at 1.3 eV (quenching with Ea = 200 meV) which we attributed to defects in the CdS layer.

KW - solar cells

KW - photoluminescence

KW - CZTSe

UR - http://iopscience.iop.org/journal/0022-3727

U2 - 10.1088/1361-6463/aaefe3

DO - 10.1088/1361-6463/aaefe3

M3 - Article

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JO - Journal of Physics D: Applied Physics

T2 - Journal of Physics D: Applied Physics

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