Formation of a ZnS/Zn(S, O) bilayer buffer on CuInS 2 thin film solar cell absorbers by chemical bath deposition

M. Bär, A. Ennaoui, J. Klaer, T. Kropp, R. Sáez-Araoz, N. Allsop, I. Lauermann, H. W. Schock, M. C. Lux-Steiner

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The application of Zn compounds as buffer layers was recently extended to wide-gap CuInS 2 (CIS) based thin film solar cells. Using an alternative chemical deposition route for the buffer preparation aiming at the deposition of a single-layer, nominal ZnS buffer without the need for any toxic reactants such as hydrazine has helped us to achieve a similar efficiency as respective CdS-buffered reference devices. In order to shed light on the differences of other Zn-compound buffers deposited in conventional chemical baths [chemical bath deposition (CBD)] compared to the buffer layers deposited by this alternative CBD process, the composition of the deposited buffers was investigated by x-ray excited Auger electron and x-ray photoelectron spectroscopy to potentially clarify their superiority in terms of device performance. We have found that in the early stages of this alternative CBD process a thin ZnS layer is formed on the CIS, whereas in the second half of the CBD the growth rate is greatly increased and Zn(S,O) with a ZnS/(ZnS+ZnO) ratio of ∼80% is deposited. Thus, a ZnS/Zn(S, O) bilayer buffer is deposited on the CIS thin film solar cell absorbers by the alternative chemical deposition route used in this investigation. No major changes of these findings after a postannealing of the buffer/CIS sample series and recharacterization could be identified.

Original languageEnglish
Article number123503
JournalJournal of Applied Physics
Issue number12
Publication statusPublished - 11 Jul 2006


ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Bär, M., Ennaoui, A., Klaer, J., Kropp, T., Sáez-Araoz, R., Allsop, N., Lauermann, I., Schock, H. W., & Lux-Steiner, M. C. (2006). Formation of a ZnS/Zn(S, O) bilayer buffer on CuInS 2 thin film solar cell absorbers by chemical bath deposition. Journal of Applied Physics, 99(12), [123503].