Thermal Conductivity and Phonon Scattering Processes of ALD Grown PbTe–PbSe Thermoelectric Thin Films
[1];
[1];
[3];
[4];
[5]
- Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville VA 22904‐4746 USA
- Department of Electrical Computer Engineering Old Dominion University Norfolk VA 23529 USA
- Department of Materials Science and Engineering University of Virginia Charlottesville VA 22904‐4746 USA
- Applied Optical Plasma Sciences Sandia National Laboratories Albuquerque NM 87123 USA
- Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville VA 22904‐4746 USA, Department of Materials Science and Engineering University of Virginia Charlottesville VA 22904‐4746 USA, Department of Physics University of Virginia Charlottesville VA 22904‐4746 USA
Abstract This work studies the thermal conductivity and phonon scattering processes in a series of n‐type lead telluride‐lead selenide (PbTe–PbSe) nanostructured thin films grown by atomic layer deposition (ALD). The ALD growth of the PbTe–PbSe samples in this work results in nonepitaxial films grown directly on native oxide/Si substrates, where the Volmer–Weber mode of growth promotes grains with a preferred columnar orientation. The ALD growth of these lead‐rich PbTe, PbSe, and PbTe–PbSe thin films results in secondary oxide phases, along with an increase microstructural quality with increased film thickness. The compositional variation and resulting point and planar defects in the PbTe–PbSe nanostructures give rise to additional phonon scattering events that reduce the thermal conductivity below that of the corresponding ALD‐grown control PbTe and PbSe films. Temperature‐dependent thermal conductivity measurements show that the phonon scattering in these ALD‐grown PbTe–PbSe nanostructured materials, along with ALD‐grown PbTe and PbSe thin films, are driven by extrinsic defect scattering processes as opposed to phonon–phonon scattering processes intrinsic to the PbTe or PbSe phonon spectra. The implication of this work is that polycrystalline, nanostructured ALD composites of thermoelectric PbTe–PbSe films are effective in reducing the phonon thermal conductivity, and represent a pathway for further improvement of the figure of merit ( ZT ), enhancing their thermoelectric application potential.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- DE‐NA0003525
- OSTI ID:
- 1560697
- Journal Information:
- Advanced Functional Materials, Journal Name: Advanced Functional Materials Vol. 29 Journal Issue: 46; ISSN 1616-301X
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
Web of Science
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