Stability of the bandgap in Cu-poor CuInSe2

Recent photoluminescence studies report that the bandgap energy Eg 1.0 eV of CuInSe2 is stable for Cu-poor compounds [Cu] [In] < 1, despite the fact that Cu vacancies and (InCu + 2VCu) complexes increase the energy gap. In this work, the impact on Eg due to the presence of native defects is analy...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2012-10, Vol.24 (45), p.455503
Main Authors: Huang, Dan, Persson, Clas
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Exact sciences and technology
Ii-vi semiconductors
Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation
Photoluminescence
Physics
Point-Defects
Semiconductors
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Summary:Recent photoluminescence studies report that the bandgap energy Eg 1.0 eV of CuInSe2 is stable for Cu-poor compounds [Cu] [In] < 1, despite the fact that Cu vacancies and (InCu + 2VCu) complexes increase the energy gap. In this work, the impact on Eg due to the presence of native defects is analyzed using a screened hybrid density functional approach. We demonstrate that the formation energy of neutral (CuIn + InCu) anti-site dimers decreases for CuInSe2 compounds when [Cu] [In] decreases. This is explained in terms of the octet rule for the Se atoms next to the (InCu + 2VCu) defects. As a consequence, Cu-poor CuInSe2 involves the large [(InCu + 2VCu) + (CuIn + InCu)] complexes where the anti-site defects stabilize Eg, in agreement with experimental findings.
ISSN:0953-8984
1361-648X
1361-648X
DOI:10.1088/0953-8984/24/45/455503