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Thermodynamics and kinetics of the copper vacancy in CuInSe2, CuGaSe2, CuInS2, and CuGaS2 from screened-exchange hybrid density functional theory

Pohl, Johan and Albe, Karsten (2010):
Thermodynamics and kinetics of the copper vacancy in CuInSe2, CuGaSe2, CuInS2, and CuGaS2 from screened-exchange hybrid density functional theory.
In: J. Appl. Phys., American Institute of Physics, pp. 109905-1, 108, (2), ISSN 0021-8979,
[Online-Edition: http://jap.aip.org/resource/1/japiau/v110/i10/p109905_s1],
[Article]

Abstract

Formation enthalpies and migration barriers of the copper vacancy in CuInSe2, CuGaSe2(2), CuInS2, and CuGaS2 are calculated by means of density functional theory with a screened-exchange hybrid functional of the Heyd-Scuseria-Ernzerhof type: The band gaps of all chalcopyrite phases are very well described by the hybrid functional using a single value for the Hartree-Fock screening parameter. The defect formation enthalpies of the copper vacancy in CuInS2 and CuGaS2 are around 0.8 eV higher than in CulnSe(2) and CuGaSe2. This results in the absence of Fermi-level pinning for CuInS2 and explains a reduced tendency of CuInS2 and CuGaS2 to form ordered defect compounds. The calculated migration barrier of the copper vacancy in CuInSe2 is 1.26 eV and of comparable magnitude for CuGaSe2, CuInS2, and CuGaS2. From this data we estimate a diffusion coefficient for CuInSe2 and show that it is in agreement with measurements of diffusion in stoichiometric single crystalline samples when direct experimental methods are used.

Item Type: Article
Erschienen: 2010
Creators: Pohl, Johan and Albe, Karsten
Title: Thermodynamics and kinetics of the copper vacancy in CuInSe2, CuGaSe2, CuInS2, and CuGaS2 from screened-exchange hybrid density functional theory
Language: English
Abstract:

Formation enthalpies and migration barriers of the copper vacancy in CuInSe2, CuGaSe2(2), CuInS2, and CuGaS2 are calculated by means of density functional theory with a screened-exchange hybrid functional of the Heyd-Scuseria-Ernzerhof type: The band gaps of all chalcopyrite phases are very well described by the hybrid functional using a single value for the Hartree-Fock screening parameter. The defect formation enthalpies of the copper vacancy in CuInS2 and CuGaS2 are around 0.8 eV higher than in CulnSe(2) and CuGaSe2. This results in the absence of Fermi-level pinning for CuInS2 and explains a reduced tendency of CuInS2 and CuGaS2 to form ordered defect compounds. The calculated migration barrier of the copper vacancy in CuInSe2 is 1.26 eV and of comparable magnitude for CuGaSe2, CuInS2, and CuGaS2. From this data we estimate a diffusion coefficient for CuInSe2 and show that it is in agreement with measurements of diffusion in stoichiometric single crystalline samples when direct experimental methods are used.

Journal or Publication Title: J. Appl. Phys.
Volume: 108
Number: 2
Publisher: American Institute of Physics
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 28 Feb 2012 14:39
Official URL: http://jap.aip.org/resource/1/japiau/v110/i10/p109905_s1
Identification Number: doi:10.1063/1.3662187
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