In Situ TEM Observation of Thermoelectric Cooling in a Bismuth Telluride and Bismuth-Antimony Telluride Nanoscale Heterojunction

ORAL

Abstract

Thermoelectrics have a wide variety of applications, but their efficiency must be improved before they become economical for non-niche applications. We demonstrate cooling in thermoelectric heterojunctions constructed from 2D flakes of exfoliated bismuth telluride and bismuth-antimony telluride using a new transmission electron microscopy (TEM)-based technique: plasmon energy expansion thermometry (PEET). PEET measures temperature by measuring the sample material’s bulk plasmon energy. The plasmon energy is related to the electron density, which in turn is related to temperature via the material’s coefficient of thermal expansion. Because the plasmon peaks in bismuth telluride and bismuth-antimony telluride are too broad to be precisely located, we evaporate indium nanoparticles near the heterojunction to serve as local nano-thermometers. Measuring the nanoparticles’ temperature as a function of the junction current, we have observed heterojunction cooling by 300C. With better ohmic contacts and improved device geometry, we hope to increase the thermoelectric efficiency of these 2D devices relative to their bulk 3D counterparts.

–

Presenters

  • Gurleen Bal

    Physics, University of California, Los Angeles, University of California, Los Angeles

Authors

  • Gurleen Bal

    Physics, University of California, Los Angeles, University of California, Los Angeles

  • Matthew Mecklenburg

    CEMMA, Univ of Southern California, Univ of Southern California, University of Southern California, Center for Electron Microscopy and Microanalysis, University of Southern California

  • William Hubbard

    Department of Physics & Astronomy, UCLA, Physics, University of California, Los Angeles, University of California, Los Angeles

  • Brian Zutter

    Department of Physics & Astronomy, UCLA, Physics, University of California, Los Angeles

  • Roshni Patil

    Physics, University of California, Los Angeles

  • WILLIAM KESSEL

    Physics, University of California, Los Angeles

  • Bozo Vareskic

    Physics, University of California, Los Angeles

  • Graydon Flatt

    Physics, University of California, Los Angeles

  • Shaul Aloni

    Lawrence Berkeley National Lab, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Laboratory, Molecular Foundry, Lawrence Berkeley National Lab

  • B. Regan

    Physics, University of California, Los Angeles, Physics , University of California, Los Angeles, University of California, Los Angeles