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  Bär, M.; Schubert, B.; Marsen, B.; Unold, T.; Wilks, R.G.; Schock, H.-W.; Pookpanratana, S.; Blum, M.; Krause, S.; Zhang, Y.; Heske, C.; Yang, W.; Weinhardt, L.: Cu₂ZnSnS₄ thin-film solar cell absorber composition revealed by energy-dispersive and soft x-ray emission spectroscopy. In: 35th IEEE Photovoltaic Specialists Conference (PVSC 2010) : Honolulu, Hawaii, USA, 20 - 25 June 2010Piscataway, NJ: IEEE, 2010. - ISBN 978-1-424-45890-5, p. 646-649

Abstract:
Different Cu2ZnSnS4 (CTZS) thin-film solar cell absorbers have been investigated by bulk-sensitive energydispersive spectroscopy (EDS) and surface-near bulksensitive soft x-ray emission spectroscopy (XES). While we find a good agreement between the computed Zn/Sn composition ratio based on the EDS and XES data, the XES determined Cu/(Zn+Sn) composition ratio significantly deviates from that based on EDS measurements for some samples. While the first can be explained by a homogenous Zn/Sn composition throughout the CTZS samples, the latter is interpreted as a variation of the Cu depth profile in the respective thinfilm solar cell absorbers.