Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 6: Photovoltaics I
HL 6.5: Talk
Monday, March 12, 2018, 10:30–10:45, EW 203
Element-specific atomic-scale structure of Cu2(Zn,Fe)SnS4 kesterite-stannite alloys — •Cora Preiss1, Konrad Ritter1, Stefanie Eckner1, Philipp Schöppe1, Susan Schorr2, and Claudia S. Schnohr1 — 1Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin & Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany
The chalcogenides Cu2ZnSnS4 (kesterite) and Cu2FeSnS4 (stannite) are interesting as potential photovoltaic absorbers being non-toxic and earth-abundant. In Cu2(Zn,Fe)SnS4, the S anions are surrounded by different local cation configurations. Therefore, Cu2ZnSnS4, Cu2FeSnS4, and their solid solutions with different Zn/(Zn+Fe) ratios were investigated with extended X-ray absorption fine structure spectroscopy. The absorption was measured at the K-edges of Cu, Zn, Sn, and Fe thus revealing the element-specific bond lengths of the material. All bond lengths are nearly independent of composition, yet they differ substantially for the different elements. While the Cu-S and Fe-S bond lengths are identical, the Zn-S and Sn-S bond lengths are larger by about ∼ 0.03 and 0.12 Å, respectively. Based on these experimental results, the S anion position is modelled for two possible cation nearest neighbour configurations. The S position is clearly different in the Zn and the Fe containing environment, leading to an intrinsic structural inhomogeneity on the submicrometer scale.