In Situ TEM Investigations on Thermoelectric Bi2Te3/Sb2Te3 Multilayers

Authors

  • Ulrich Schürmann,

    1. Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University Kiel Kaiserstraße 2, D-24143 Kiel, (Germany)
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  • Markus Winkler,

    1. Fraunhofer-Institute for Physical Measurement Techniques IPM, Thermoelectric Systems Heidenhofstraße 8, D-79110 Freiburg, (Germany)
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  • Jan D. König,

    1. Fraunhofer-Institute for Physical Measurement Techniques IPM, Thermoelectric Systems Heidenhofstraße 8, D-79110 Freiburg, (Germany)
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  • Xi Liu,

    1. Institute of Inorganic Chemistry, Christian Albrechts University Kiel Max-Eyth-Straße 2, D-24118 Kiel, (Germany)
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  • Viola Duppel,

    1. Max Planck Institute for Solid State Research, Stuttgart Heisenbergstraße 1, D-70569 Stuttgart, (Germany)
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  • Wolfgang Bensch,

    1. Institute of Inorganic Chemistry, Christian Albrechts University Kiel Max-Eyth-Straße 2, D-24118 Kiel, (Germany)
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  • Harald Böttner,

    1. Fraunhofer-Institute for Physical Measurement Techniques IPM, Thermoelectric Systems Heidenhofstraße 8, D-79110 Freiburg, (Germany)
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  • Lorenz Kienle

    Corresponding author
    1. Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University Kiel Kaiserstraße 2, D-24143 Kiel, (Germany)
    • Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University Kiel Kaiserstraße 2, D-24143 Kiel, Germany.
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  • The authors would like to thank Prof. Dr. Dr. h. c. mult. A. Simon for enabling the TEM experiments and Christin Szillus for the FIB preparation. Financial support by the DFG in the frame of the priority program SPP1386 “Nanostructured Thermoelectric Materials” is gratefully acknowledged.

Abstract

In this work, the impact of heat treatment on the real structure of Bi2Te3/Sb2Te3 multilayers is investigated. The material was heated in situ in the transmission electron microscope (TEM) and ex situ inside a furnace after preparing these layers with the so-called nanoalloying deposition technique via molecular beam epitaxy (MBE) equipment. The samples were prepared as a lamella for TEM studies using focused ion beam technique. EDX elemental mapping and high angle annular dark field mode-STEM were performed to monitor changes of the morphology and interdiffusion phenomena after heating up to 250 °C. A grain growth started during heating and the chemical layer structure was smeared out partly but remained in several grains and was found to be adjusted parallel to a major lattice plane in a crystallite. High resolution TEM shows polysynthetic twinning in a number of crystals.

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