Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 21: Photo-voltaics II
HL 21.4: Vortrag
Dienstag, 13. März 2018, 14:45–15:00, EW 202
Thermal Conductivity in Kesterite Crystals — •Martin Handwerg1,2, Rüdiger Mitdank1, Laura-Elisa Valle-Rios2,3, Sergej Levcenco2, Thomas Unold2, Susan Schorr2,3, and Saskia F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 14109 Berlin, Germany — 3Free University Berlin, Institute of Geological Sciences, 14195 Berlin, Germany
The kesterite materials Copper-Zinc-Tin-Sulfide (CZTS) and -Selenide (CZTSe) are of huge interest for future solar cell applications, due to the ideal band gap and high absorption rate. Insight in the thermal conductivity of a solar absorption material is important for the thermal management of the cell and therefore for the temperature-dependent efficiency.
However, thermal conductivity investigations are rare.
Here we used the 3ω-method to investigate the thermal conductivity of CZTS and CZTSe macro-crystals.
The crystal thicknesses were in the range of several hundred micrometers. The metal heater lines with a width of 10 µm were deposited on the polished crystal surface.
The measured thermal conductivity is about 3−5 Wm−1K−1.
The measured temperature dependence of the thermal conductivity allows conclusions concerning the transport process. Phonon-phonon-Umklapp-scattering dominates the thermal conductivity for T>180 K and point-defect-scattering occurs for T<180 K. With these two scattering processes there is a maximum of the thermal conductivity at T=100 K with increased conductivity values up to 8 Wm−1K−1.