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Anufriev R, Ohori D, Wu Y, Yanagisawa R, Jalabert L, Samukawa S, Nomura M. Impact of nanopillars on phonon dispersion and thermal conductivity of silicon membranes. NANOSCALE 2023; 15:2248-2253. [PMID: 36628951 DOI: 10.1039/d2nr06266f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The performance of silicon-based thermoelectric energy generators is limited by the high thermal conductivity of silicon. Theoretical works have long proposed reducing the thermal conductivity by resonant phonon modes in nanopillars placed on the surface of silicon films. However, these predictions have never been confirmed due to the difficulty in the nanofabrication and measurements of such nanoscale systems. In this work, we report on the fabrication and measurements of silicon films with nanopillars as small as 12 nm in diameter. Our Brillouin light scattering spectroscopy experiments revealed that nanopillars indeed host resonant phonon modes. Yet, our thermal measurements using the micro time-domain thermoreflectance technique showed only a statistically insignificant difference between the thermal properties of silicon membranes with and without nanopillars. Results of this work contrast with the predictions of a substantial reduction in the thermal conductivity due to nanopillars and suggest refining the simulations to account for realistic experimental conditions.
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Affiliation(s)
- Roman Anufriev
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
| | - Daisuke Ohori
- Institute of Fluid Science, Tohoku University, Sendai, 980-8577, Japan
| | - Yunhui Wu
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
| | - Ryoto Yanagisawa
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
| | - Laurent Jalabert
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
- Laboratory for Integrated Micro Mechatronic Systems/National Center for Scientific Research-Institute of Industrial Science (LIMMS/CNRS-IIS), The University of Tokyo, Tokyo 153-8505, Japan
| | - Seiji Samukawa
- Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan
- Joint Research Center of National Yang Ming Chiao Tung University and Tohoku University, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan
- Institute of Fluid Science, Tohoku University, Sendai, 980-8577, Japan
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Masahiro Nomura
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
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Cheng Y, Xiong S, Zhang T. Enhancing the Coherent Phonon Transport in SiGe Nanowires with Dense Si/Ge Interfaces. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:4373. [PMID: 36558226 PMCID: PMC9781128 DOI: 10.3390/nano12244373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
The manipulation of phonon transport with coherent waves in solids is of fundamental interest and useful for thermal conductivity design. Based on equilibrium molecular dynamics simulations and lattice dynamics calculations, the thermal transport in SiGe superlattice nanowires with a tuned Si/Ge interface density was investigated by using the core-shell and phononic structures as the primary stacking layers. It was found that the thermal conductivity decreased with the increase of superlattice period lengths (Lp) when Lp was larger than 4 nm. This is because introducing additional Si/Ge interfaces can enhance phonon scattering. However, when Lp<4 nm, the increased interface density could promote heat transfer. Phonon density-of-state analysis demonstrates that new modes between 10 and 14 THz are formed in structures with dense Si/Ge interfaces, which is a signature of coherent phonon transport as those modes do not belong to bulk Si or Ge. The density of the newly generated modes increases with the increase of interface density, leading to an enhanced coherent transport. Besides, with the increase of interface density, the energy distribution of the newly generated modes becomes more balanced on Si and Ge atoms, which also facilitates heat transfer. Our current work is not only helpful for understanding coherent phonon transport but also beneficial for the design of new materials with tunable thermal conductivity.
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Affiliation(s)
- Yajuan Cheng
- School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
| | - Shiyun Xiong
- Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
- Laboratory for Integrated Micro Mechatronic Systems (LIMMS/CNRS-IIS), The University of Tokyo, Tokyo 153-8505, Japan
| | - Tao Zhang
- School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
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Ma J. Phonon Engineering of Micro‐ and Nanophononic Crystals and Acoustic Metamaterials: A Review. SMALL SCIENCE 2022. [DOI: 10.1002/smsc.202200052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Jihong Ma
- Department of Mechanical Engineering University of Vermont Burlington VT 05405 USA
- Materials Science Program University of Vermont Burlington VT 05405 USA
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Cocemasov A, Brinzari V, Jeong DG, Korotcenkov G, Vatavu S, Lee JS, Nika DL. Thermal Transport Evolution Due to Nanostructural Transformations in Ga-Doped Indium-Tin-Oxide Thin Films. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1126. [PMID: 33925345 PMCID: PMC8146152 DOI: 10.3390/nano11051126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/22/2022]
Abstract
We report on a comprehensive theoretical and experimental investigation of thermal conductivity in indium-tin-oxide (ITO) thin films with various Ga concentrations (0-30 at. %) deposited by spray pyrolysis technique. X-ray diffraction (XRD) and scanning electron microscopy have shown a structural transformation in the range 15-20 at. % Ga from the nanocrystalline to the amorphous phase. Room temperature femtosecond time domain thermoreflectance measurements showed nonlinear decrease of thermal conductivity in the range 2.0-0.5 Wm-1 K-1 depending on Ga doping level. It was found from a comparison between density functional theory calculations and XRD data that Ga atoms substitute In atoms in the ITO nanocrystals retaining Ia-3 space group symmetry. The calculated phonon dispersion relations revealed that Ga doping leads to the appearance of hybridized metal atom vibrations with avoided-crossing behavior. These hybridized vibrations possess shortened mean free paths and are the main reason behind the thermal conductivity drop in nanocrystalline phase. An evolution from propagative to diffusive phonon thermal transport in ITO:Ga with 15-20 at. % of Ga was established. The suppressed thermal conductivity of ITO:Ga thin films deposited by spray pyrolysis may be crucial for their thermoelectric applications.
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Affiliation(s)
- Alexandr Cocemasov
- E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, MD-2009 Chisinau, Moldova; (A.C.); (V.B.); (G.K.)
| | - Vladimir Brinzari
- E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, MD-2009 Chisinau, Moldova; (A.C.); (V.B.); (G.K.)
| | - Do-Gyeom Jeong
- Laboratory for Spectroscopy of Condensed Matter Physics, Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (D.-G.J.); (J.S.L.)
| | - Ghenadii Korotcenkov
- E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, MD-2009 Chisinau, Moldova; (A.C.); (V.B.); (G.K.)
| | - Sergiu Vatavu
- Physics of Semiconductors and Devices Laboratory, Department of Physics and Engineering, Moldova State University, MD-2009 Chisinau, Moldova;
| | - Jong S. Lee
- Laboratory for Spectroscopy of Condensed Matter Physics, Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (D.-G.J.); (J.S.L.)
| | - Denis L. Nika
- E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, MD-2009 Chisinau, Moldova; (A.C.); (V.B.); (G.K.)
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