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Band gap fluctuations in Cu(In,Ga)Se2 thin films

Published online by Cambridge University Press:  01 February 2011

Julian Mattheis ,
Thomas Schlenker ,
Martin Bogicevic ,
Uwe Rau  and
Jürgen H. Werner
Julian Mattheis
Affiliation:
Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart e-mail: julian.mattheis@ipe.uni-stuttgart.de
Thomas Schlenker
Affiliation:
Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart e-mail: julian.mattheis@ipe.uni-stuttgart.de
Martin Bogicevic
Affiliation:
Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart e-mail: julian.mattheis@ipe.uni-stuttgart.de
Uwe Rau
Affiliation:
Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart e-mail: julian.mattheis@ipe.uni-stuttgart.de
Jürgen H. Werner
Affiliation:
Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart e-mail: julian.mattheis@ipe.uni-stuttgart.de
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Abstract

A simple statistical model describes measured absorption and photoluminescence data of Cu(In1-x, Gax)Se2 thin films. The broadening of the transition peak in the absorption spectra stems from band gap fluctuations. The extent of the spatial inhomogeneities as expressed in the standard deviation Eg μ reaches a maximum of Eg μ = 90 meV for films with equal amounts of indium and gallium, indicating alloy disorder as one possible source of the band gap fluctuations. The fluctuations observed lead to a decrease δVOC of the maximum possible open-circuit voltage VOC of almost 150 mV. However, the experimentally measured, low VOC of solar cells with high gallium content cannot be explained by band gap fluctuations alone. Consequently, our analysis suggests that the dominant recombination process in Cu(In1-x, Gax)Se2 thin film solar cells with high gallium content is not governed by the band gap energy, but is more likely due to deep levels within the forbidden gap.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 865: Symposium F – Thin-Film Compound Semiconductor Photovoltaics , 2005 , F16.4
Copyright
Copyright © Materials Research Society 2005

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References

[1] Rau, U. and Werner, J. H., Appl. Phys. Lett. 84, 3735 (2004)Google Scholar
[2] Werner, J. H., Mattheis, J., and Rau, U., Thin Solid Films, in pressGoogle Scholar
[3] Orgassa, K., Coherent optical analysis of the ZnO/CdS/Cu(In,Ga)Se2 thin film solar cell, PhD Thesis, University of Stuttgart (2004)Google Scholar
[4] Bothe, K., Bauer, G. H., and Unold, T., Thin Solid Films 403, 453 (2002)Google Scholar
[5] Gabor, A. M., Tuttle, J. R., Albin, D. S., Contreras, M. A., Noufi, R., Hermann, A. M., Appl. Phys. Lett. 65, 198 (1994)Google Scholar
[6] Mattheis, J., Rau, U., and Werner, J. H., unpublishedGoogle Scholar
[7] Dirnstorfer, I., Wagner, M., Hofmann, D. M., Lampert, M. D., Karg, F., and Meyer, B. K., Phys. Stat. Sol (a) 168, 163 (1998)Google Scholar
[8] Schlenker, T., Growth of Cu(In,Ga)Se2 thin films, PhD Thesis, handed in to the University of Stuttgart Google Scholar
[9] Shockley, W. and Queisser, H. J., J. Appl. Phys. 32, 510 (1961)Google Scholar