Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 25: Poster 1
HL 25.32: Poster
Wednesday, September 7, 2022, 18:00–20:00, P2
Effect of gallium content on the grain boundary properties of polycrystalline Cu(In,Ga)Se2 absorber layers in thin-film solar cells — •Sinju Thomas1, Wolfram Witte2, Dimitrios Hariskos2, Stefan Paetel2, Chang-Yun Song3, Heiko Kempa3, Nora El-Ganainy4, and Daniel Abou-Ras1 — 1Helmholtz Zentrum Berlin für Materialien und Energie (HZB) — 2Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany — 3Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Fachgruppe Photovoltaik — 4Competence Centre Photovoltaics Berlin (PVcomB)/(HZB)
In the present work, we apply several scanning electron microscopy techniques in a correlative manner on five solar cells with different ([Ga]/([Ga]+[In]) GGIs (0.13, 0.34, 0.51, 0.67, and 0.83) in the Cu(In,Ga)Se2 photoabsorbers, in addition to time-resolved photoluminescence and quantum-efficiency measurements. Grain sizes, electron lifetimes, grain-boundary (GB) recombination velocities, elemental distributions within the absorber layer, as well as luminescence emission distributions were assessed for all five samples. Owing to much reduced grain size at a GGI of 0.83,there is a high density of GBs that serve as active recombination centers. At this GGI, Voc losses via non-radiative recombination deteriorates the device efficiency However, the effective GB recombination velocity does not vary linearly with the increasing GGI. Distribution of the recombination velocities at individual GBs suggests that upward and downward band bending at GBs is independent of the Ga concentration