Feedback mechanism for the stability of the band gap of CuInSe2

Levent Guetay; David Regesch; Jes K. Larsen; Yasuhiro Aida; Valerie Depredurand; Alex Redinger; Sabina Caneva; Susan Schorr; Christiane Stephan; Julien Vidal; Silvana Botti; Susanne Siebentritt

doi:10.1103/PhysRevB.86.045216

Feedback mechanism for the stability of the band gap of CuInSe2

Levent Guetay, David Regesch, Jes K. Larsen, Yasuhiro Aida, Valerie Depredurand, Alex Redinger, Sabina Caneva, Susan Schorr, Christiane Stephan, Julien Vidal, Silvana Botti, Susanne Siebentritt

Physics

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33 Citations (Scopus)

Abstract

We report on experimental results on band gap and lattice distortion in CuInSe2 for various degrees of Cu deficiency. The band gap is measured by optical methods, and the Cu vacancy density and anion displacement parameter are determined by neutron scattering. Our data show that the band gap decreases for Cu-poor compositions, and the anion displacement is weakly dependent on the concentration of Cu vacancies. This is in apparent contradiction with ab initio calculations that always predict a larger band gap in presence of Cu vacancies. To shed light on this issue, we studied the overall dependence of the band gap on the anion displacement and on the concentration of Cu vacancies using a self-consistent GW approach and hybrid functionals, including a feedback mechanism that was recently proposed. Our calculations illustrate consistently the remarkable stability of the band gap of chalcopyrite semiconductors and explain the experimental observations by a coupled effect of Cu vacancies and lattice distortions within the feedback model.

Original language	English
Article number	045216
Pages (from-to)	-
Number of pages	5
Journal	Physical Review B (Condensed Matter and Materials Physics)
Volume	86
Issue number	4
DOIs	https://doi.org/10.1103/PhysRevB.86.045216
Publication status	Published - 27 Jul 2012

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abstract = "We report on experimental results on band gap and lattice distortion in CuInSe2 for various degrees of Cu deficiency. The band gap is measured by optical methods, and the Cu vacancy density and anion displacement parameter are determined by neutron scattering. Our data show that the band gap decreases for Cu-poor compositions, and the anion displacement is weakly dependent on the concentration of Cu vacancies. This is in apparent contradiction with ab initio calculations that always predict a larger band gap in presence of Cu vacancies. To shed light on this issue, we studied the overall dependence of the band gap on the anion displacement and on the concentration of Cu vacancies using a self-consistent GW approach and hybrid functionals, including a feedback mechanism that was recently proposed. Our calculations illustrate consistently the remarkable stability of the band gap of chalcopyrite semiconductors and explain the experimental observations by a coupled effect of Cu vacancies and lattice distortions within the feedback model.",

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T1 - Feedback mechanism for the stability of the band gap of CuInSe2

AU - Guetay, Levent

AU - Regesch, David

AU - Larsen, Jes K.

AU - Aida, Yasuhiro

AU - Depredurand, Valerie

AU - Redinger, Alex

AU - Caneva, Sabina

AU - Schorr, Susan

AU - Stephan, Christiane

AU - Vidal, Julien

AU - Botti, Silvana

AU - Siebentritt, Susanne

PY - 2012/7/27

Y1 - 2012/7/27

N2 - We report on experimental results on band gap and lattice distortion in CuInSe2 for various degrees of Cu deficiency. The band gap is measured by optical methods, and the Cu vacancy density and anion displacement parameter are determined by neutron scattering. Our data show that the band gap decreases for Cu-poor compositions, and the anion displacement is weakly dependent on the concentration of Cu vacancies. This is in apparent contradiction with ab initio calculations that always predict a larger band gap in presence of Cu vacancies. To shed light on this issue, we studied the overall dependence of the band gap on the anion displacement and on the concentration of Cu vacancies using a self-consistent GW approach and hybrid functionals, including a feedback mechanism that was recently proposed. Our calculations illustrate consistently the remarkable stability of the band gap of chalcopyrite semiconductors and explain the experimental observations by a coupled effect of Cu vacancies and lattice distortions within the feedback model.

AB - We report on experimental results on band gap and lattice distortion in CuInSe2 for various degrees of Cu deficiency. The band gap is measured by optical methods, and the Cu vacancy density and anion displacement parameter are determined by neutron scattering. Our data show that the band gap decreases for Cu-poor compositions, and the anion displacement is weakly dependent on the concentration of Cu vacancies. This is in apparent contradiction with ab initio calculations that always predict a larger band gap in presence of Cu vacancies. To shed light on this issue, we studied the overall dependence of the band gap on the anion displacement and on the concentration of Cu vacancies using a self-consistent GW approach and hybrid functionals, including a feedback mechanism that was recently proposed. Our calculations illustrate consistently the remarkable stability of the band gap of chalcopyrite semiconductors and explain the experimental observations by a coupled effect of Cu vacancies and lattice distortions within the feedback model.

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DO - 10.1103/PhysRevB.86.045216

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JO - Physical Review B (Condensed Matter and Materials Physics)

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Feedback mechanism for the stability of the band gap of CuInSe2

Abstract

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