Length scale dependence of the thermal conductivity accumulation in nanograined Si-Ge alloys

ORAL

Abstract

The manipulation of the lattice thermal conductivity without significantly effecting electronic mobility is a crucial part to optimize the thermoelectric figure of merit. In order to fully understand the contributions to the lattice thermal conductivity, a calculation of the lattice thermal conductivity based on a phonon frequency-dependent model, derived using the effective medium method, is presented. This model predicts the lattice thermal conductivity of the fully nanostructured systems, and helps to understand the dependence of lattice thermal conductivity on various length scales. The simulation results are validated with experimental results obtained via time-domain thermoreflectance. By varying the modulation frequency of the pump-probe technique, the thermal conductivity of Si and Si-Ge systems over a variety of thermal penetration depths is measured. The combination of modeling and experimental findings shows insight into length scale effect on phonon wavelength and mean free path, as well as the resulting impact on the thermal conductivity.

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Authors

  • Long Chen

    University of Virginia

  • Jonathan Tan

    Duquesne University, Baker Hughes, Hampton University, Korea Research Institute of Standards and Science, Electronics and Telecommunications Research Institute, Texas Christian University, University of North Texas Health Science Center, Austin Peay State University, Virginia Military Institute, Pennsylvania State University, University of Virginia, Washington University, National Institute for Materials Science, Japan, Tokyo Metropolitan University, Japan, Univ of Kentucky, Argonne National Laboratory, Oak Ridge National Laboratory, Univ of Virginia, James Madison University, Department of Chemistry & Biochemistry, High Point University, Department of Chemistry, High Point University, Department of Physics, James Madison University, Department of Physics & Astronomy, Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, Institute of Renewable Energy and Environment Technology, University of Bolton, Bolton, UK, Division of Materials Science and Engineering, Ames Laboratory, US Dept. of Energy, Ames, IA, Lehigh University, University of Pardubice, Universite de Rennes, Jan Dlugosz University, Translume, NSCL/FRIB, Duke University, University of Massachusetts - Amherst, University of St. Andrews, National Radio Astronomy Observatory, University of Florida, Yale University, None, Georgia College & State Univ, Georgia College & State University, National University of Sciences and Technology (NUST), Univ of Tennessee Space Inst, The University of Virginia, Chiang Mai University, DHA Suffa University, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic, Department of Physics and Astronomy, Austin Peay State University, Clarksville, TN, United States, George Mason University, Northern Virginia Community College, Department of Physics, University of Virginia, Istanbul University, Georgia College and State University, University of Houston, Western Kentucky Univ, James Madison University, Virginia Polytechnic Institute and State University, Pontifica Universidad Catolica de Chile, Trent University, Univ of Arizona, Ohio State University, NRAO, University of Virginia/NRAO

  • Jonathan Tan

    Duquesne University, Baker Hughes, Hampton University, Korea Research Institute of Standards and Science, Electronics and Telecommunications Research Institute, Texas Christian University, University of North Texas Health Science Center, Austin Peay State University, Virginia Military Institute, Pennsylvania State University, University of Virginia, Washington University, National Institute for Materials Science, Japan, Tokyo Metropolitan University, Japan, Univ of Kentucky, Argonne National Laboratory, Oak Ridge National Laboratory, Univ of Virginia, James Madison University, Department of Chemistry & Biochemistry, High Point University, Department of Chemistry, High Point University, Department of Physics, James Madison University, Department of Physics & Astronomy, Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, Institute of Renewable Energy and Environment Technology, University of Bolton, Bolton, UK, Division of Materials Science and Engineering, Ames Laboratory, US Dept. of Energy, Ames, IA, Lehigh University, University of Pardubice, Universite de Rennes, Jan Dlugosz University, Translume, NSCL/FRIB, Duke University, University of Massachusetts - Amherst, University of St. Andrews, National Radio Astronomy Observatory, University of Florida, Yale University, None, Georgia College & State Univ, Georgia College & State University, National University of Sciences and Technology (NUST), Univ of Tennessee Space Inst, The University of Virginia, Chiang Mai University, DHA Suffa University, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic, Department of Physics and Astronomy, Austin Peay State University, Clarksville, TN, United States, George Mason University, Northern Virginia Community College, Department of Physics, University of Virginia, Istanbul University, Georgia College and State University, University of Houston, Western Kentucky Univ, James Madison University, Virginia Polytechnic Institute and State University, Pontifica Universidad Catolica de Chile, Trent University, Univ of Arizona, Ohio State University, NRAO, University of Virginia/NRAO

  • Jonathan Tan

    Duquesne University, Baker Hughes, Hampton University, Korea Research Institute of Standards and Science, Electronics and Telecommunications Research Institute, Texas Christian University, University of North Texas Health Science Center, Austin Peay State University, Virginia Military Institute, Pennsylvania State University, University of Virginia, Washington University, National Institute for Materials Science, Japan, Tokyo Metropolitan University, Japan, Univ of Kentucky, Argonne National Laboratory, Oak Ridge National Laboratory, Univ of Virginia, James Madison University, Department of Chemistry & Biochemistry, High Point University, Department of Chemistry, High Point University, Department of Physics, James Madison University, Department of Physics & Astronomy, Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA, Institute of Renewable Energy and Environment Technology, University of Bolton, Bolton, UK, Division of Materials Science and Engineering, Ames Laboratory, US Dept. of Energy, Ames, IA, Lehigh University, University of Pardubice, Universite de Rennes, Jan Dlugosz University, Translume, NSCL/FRIB, Duke University, University of Massachusetts - Amherst, University of St. Andrews, National Radio Astronomy Observatory, University of Florida, Yale University, None, Georgia College & State Univ, Georgia College & State University, National University of Sciences and Technology (NUST), Univ of Tennessee Space Inst, The University of Virginia, Chiang Mai University, DHA Suffa University, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic, Department of Physics and Astronomy, Austin Peay State University, Clarksville, TN, United States, George Mason University, Northern Virginia Community College, Department of Physics, University of Virginia, Istanbul University, Georgia College and State University, University of Houston, Western Kentucky Univ, James Madison University, Virginia Polytechnic Institute and State University, Pontifica Universidad Catolica de Chile, Trent University, Univ of Arizona, Ohio State University, NRAO, University of Virginia/NRAO