Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 6: Photovoltaics I
HL 6.7: Talk
Monday, March 12, 2018, 11:00–11:15, EW 203
Atomic-scale structure of Cu2Zn(Sn,Ge)Se4 kesterite alloys — •Konrad Ritter1, Cora Preiß1, Galina Gurieva2, René Gunder2, Stefanie Eckner1, Roman Chernikov3, Edmund Welter3, Susan Schorr2,4, 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, Germany — 3Deutsches Elektronen Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany — 4Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany
Kesterites offer a wide range of promising absorber materials for photovoltaics, but the record efficiency has not exceeded 12.6% yet. Alloying Sn with Ge or replacing it completely has been used in many different approaches in the literature. However, doing so might change the local structure of the material, which has been shown to influence macroscopic material properties such as the band gap energy. Extended X-ray Absorbtion Fine Structure Spectroscopy allows the local interatomic bond lengths to be probed and correlated with Ge content or off-stoichiometry of Cu2Zn(Sn,Ge)Se4 powder samples from solid state reactions. For the Cu2Zn(Sn,Ge)Se4 alloys it can be seen, that Ge uses the least space in the lattice and Sn the most. Furthermore, the nearest neighbour bond lengths do not change significantly with composition. This holds true for off-stoichiometric Cu2ZnGeSe4 samples as well.