Semiconductor Thermal and Electrical Properties Decoupled by Localized Phonon Resonances.

Autor: Spann BT; Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Boulder, CO, 80302, USA., Weber JC; Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Boulder, CO, 80302, USA., Brubaker MD; Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Boulder, CO, 80302, USA., Harvey TE; Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Boulder, CO, 80302, USA., Yang L; School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, China., Honarvar H; Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, 80303, USA., Tsai CN; Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, 80303, USA., Treglia AC; Department of Physics, University of Colorado Boulder, Boulder, CO, 80302, USA., Lee M; Department of Physics, University of Colorado Boulder, Boulder, CO, 80302, USA., Hussein MI; Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, 80303, USA.; Department of Physics, University of Colorado Boulder, Boulder, CO, 80302, USA., Bertness KA; Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Boulder, CO, 80302, USA.
Jazyk: angličtina
Zdroj: Advanced materials (Deerfield Beach, Fla.) [Adv Mater] 2023 Jun; Vol. 35 (26), pp. e2209779. Date of Electronic Publication: 2023 May 10.
DOI: 10.1002/adma.202209779
Abstrakt: Thermoelectric materials convert heat into electricity through thermally driven charge transport in solids or vice versa for cooling. To compete with conventional energy-conversion technologies, a thermoelectric material must possess the properties of both an electrical conductor and a thermal insulator. However, these properties are normally mutually exclusive because of the interconnection between scattering mechanisms for charge carriers and phonons. Recent theoretical investigations on sub-device scales have revealed that nanopillars attached to a membrane exhibit a multitude of local phonon resonances, spanning the full spectrum, that couple with the heat-carrying phonons in the membrane and cause a reduction in the in-plane thermal conductivity, with no expected change in the electrical properties because the nanopillars are outside the pathway of voltage generation and charge transport. Here this effect is demonstrated experimentally for the first time by investigating device-scale suspended silicon membranes with GaN nanopillars grown on the surface. The nanopillars cause up to 21% reduction in the thermal conductivity while the power factor remains unaffected, thus demonstrating an unprecedented decoupling in the semiconductor's thermoelectric properties. The measured thermal conductivity behavior for coalesced nanopillars and corresponding lattice-dynamics calculations provide evidence that the reductions are mechanistically tied to the phonon resonances. This finding paves the way for high-efficiency solid-state energy recovery and cooling.
(© 2023 Wiley-VCH GmbH.)
Databáze: MEDLINE
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