Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 42: Perovskite and Photovoltaics II (joint session HL/KFM)
HL 42.2: Talk
Thursday, March 21, 2024, 09:45–10:00, EW 203
Crystallization and defect properties in combinatorially synthesized BaZrS3 thin films — •Adriana Röttger1, Jack Van Sambeek2, Marin Rusu1, Hannes Hempel1, Rafael Jaramillo2, and Thomas Unold1 — 1Helmholtz-Zentrum Berlin, Deutschland — 2Massachusetts Institute of Technology, Cambridge, MA, USA
BaZrS3 is a chalcogenide perovskite composed of Earth-abundant elements with potential applications for photovoltaic (PV) energy conversion. Using pulsed laser deposition, oxide precursors with a lateral [Ba]/[Zr] ratio, ranging from 0.8 to 1.3, were deposited on 50 x 12 mm2 large samples, which were then sulfurized in a tube furnace using different concentrations of H2S in Ar gas at temperatures ranging from 800∘C to 1000∘C. The combinatorial nature of the thin films allows the study of crystallization behavior dependent on the composition of the material. A considerable increase in crystallite size was observed from the Zr-rich side to the Ba-rich side of all samples using grazing incidence x-ray diffraction and scanning electron microscopy. We hypothesize that Ba excess leads to liquid phase assisted growth, similar to a low temperature growth mechanism reported recently by Yang et al.[1] We demonstrate control over the kinetics of crystallization by varying temperature and/or H2S partial pressure. We find that band-edge photoluminescence (PL) increases from the Ba-rich to the Zr-rich side, while defect state PL probed at low temperatures show a reverse trend. This suggests that careful control of the metals ratio will be key to achieving thin films with large crystals and good PV performance. [1] Yang et al., Chemistry of Materials 2023 35 (12), 4743-4750
Keywords: chalkogenides; perovskites; combinatorial