Stability of the bandgap in Cu-poor CuInSe2
2012 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 24, no 45, 455503- p.Article in journal (Refereed) Published
Recent photoluminescence studies report that the bandgap energy E-g approximate to 1.0 eV of CuInSe2 is stable for Cu-poor compounds [Cu]/[In] < 1, despite the fact that Cu vacancies and (In-Cu + 2V(Cu)) complexes increase the energy gap. In this work, the impact on E-g due to the presence of native defects is analyzed using a screened hybrid density functional approach. We demonstrate that the formation energy of neutral (Cu-In + In-Cu) 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 (In-Cu + 2V(Cu)) defects. As a consequence, Cu-poor CuInSe2 involves the large [(In-Cu + 2V(Cu)) + (Cu-In + In-Cu)] complexes where the anti-site defects stabilize E-g, in agreement with experimental findings.
Place, publisher, year, edition, pages
2012. Vol. 24, no 45, 455503- p.
IdentifiersURN: urn:nbn:se:kth:diva-107068DOI: 10.1088/0953-8984/24/45/455503ISI: 000310571800010ScopusID: 2-s2.0-84867967049OAI: oai:DiVA.org:kth-107068DiVA: diva2:575012
FunderSwedish Research Council
QC 201212072012-12-072012-12-062012-12-07Bibliographically approved