Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
Benoît Reynier
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
Iléane Tiphaine Françoise Marie Lefevre
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland
Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner-Platz 1, 14109 Berlin, Germany
Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner-Platz 1, 14109 Berlin, Germany; Institute of Geological Sciences, Freie Universitaet Berlin , Maltese St. 74-100, 12249 Berlin, Germany
Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner-Platz 1, 14109 Berlin, Germany
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland; Institute of Physics, Faculty of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner-Platz 1, 14109 Berlin, Germany; Humboldt University of Berlin , Unter den Linden 6, 10117 Berlin, Germany
Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , 1015 Lausanne, Switzerland; Transport at Nanoscale Interfaces Laboratory, Swiss Federal Laboratories for Material Science and Technology (EMPA) Ueberlandstrasse 129 , 8600 Duebendorf, Switzerland
Barium zirconium sulfide (BaZrS _3 ) is an earth-abundant and environmentally friendly chalcogenide perovskite with promising properties for various energy conversion applications. Recently, sulfurization of oxide precursors has been suggested as a viable solution for effective synthesis, especially from the perspective of circumventing the difficulty of handling alkali earth metals. In this work, we explore in detail the synthesis of BaZrS _3 from Ba-Zr-O oxide precursor films sulfurized at temperatures ranging from 700 °C to 1000 °C. We propose a formation mechanism of BaZrS _3 based on a two-step reaction involving an intermediate amorphization step of the BaZrO _3 crystalline phase. We show how the diffusion of sulfur (S) species in the film is the rate-limiting step of this reaction. The processing temperature plays a key role in determining the total fraction of conversion from oxide to sulfide phase at a constant flow rate of the sulfur-containing H _2 S gas used as a reactant. Finally, we observe the formation of stoichiometric BaZrS _3 (1:1:3), even under Zr-rich precursor conditions, with the formation of ZrO _2 as a secondary phase. This marks BaZrS _3 quite unique among the other types of chalcogenides, such as chalcopyrites and kesterites, which can instead accommodate quite a large range of non-stoichiometric compositions. This work opens up a pathway for further optimization of the BaZrS _3 synthesis process, straightening the route towards future applications of this material.
