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HL: Fachverband Halbleiterphysik

HL 64: Poster: Photovoltaics and Optics

HL 64.29: Poster

Wednesday, March 22, 2017, 15:00–19:00, P1C

Approaches for the incorporation of Ge into wet-chemically produced Cu₂ZnSn(S,Se)₄ solar cells — •Michael Wolf¹, Markus Neuwirth¹, Elisabeth Seydel¹, Thomas Schnabel², Erik Ahlswede², Willi Kogler², Heinz Kalt¹, and Michael Hetterich¹ — ¹Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — ²Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart, Germany

Cu₂ZnSn(S,Se)₄ (CZTSSe) is a promising absorber material for thin film solar cells. As has been demonstrated, it can easily be doped with elements like germanium, lithium or sodium, leading to improvements in energy conversion efficiency. Germanium on the one hand is said to be a catalyst for CZTSSe grain growth when used in small amounts during annealing. On the other hand, its substitution of tin in CZTSSe increases the band gap enabling a better match to the solar spectrum and an enhanced open-circuit voltage. In this contribution we utilize two approaches to incorporate Ge into CZTSSe. First the influence of a thin doctor-bladed germanium oxide (GeOx) layer underneath and on top of the precursor on grain growth and solar cell parameters is studied. Furthermore, germanium sulfide (GeS) is used during the annealing process to tune the band gap.