Investigation of phonon coherence and backscattering using silicon nanomeshes
| Autor: | Deirdre L. Olynick, Jaeho Lee, Woochul Lee, Jeffrey J. Urban, Peidong Yang, Geoff Wehmeyer, Stefano Cabrini, Chris Dames, Scott Dhuey |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Particle system
Multidisciplinary Materials science Silicon Condensed matter physics Phonon Science General Physics and Astronomy chemistry.chemical_element 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology 01 natural sciences General Biochemistry Genetics and Molecular Biology Article Thermal conductivity Thermal transport chemistry Aperiodic graph 0103 physical sciences Thermal 010306 general physics 0210 nano-technology Coherence (physics) |
| Zdroj: | Nature Communications Nature Communications, Vol 8, Iss 1, Pp 1-8 (2017) Lee, J; Lee, W; Wehmeyer, G; Dhuey, S; Olynick, DL; Cabrini, S; et al.(2017). Investigation of phonon coherence and backscattering using silicon nanomeshes. Nature Communications, 8. doi: 10.1038/ncomms14054. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/81v1159x Nature communications, vol 8, iss 1 |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/ncomms14054. |
| Popis: | Phonons can display both wave-like and particle-like behaviour during thermal transport. While thermal transport in silicon nanomeshes has been previously interpreted by phonon wave effects due to interference with periodic structures, as well as phonon particle effects including backscattering, the dominant mechanism responsible for thermal conductivity reductions below classical predictions still remains unclear. Here we isolate the wave-related coherence effects by comparing periodic and aperiodic nanomeshes, and quantify the backscattering effect by comparing variable-pitch nanomeshes. We measure identical (within 6% uncertainty) thermal conductivities for periodic and aperiodic nanomeshes of the same average pitch, and reduced thermal conductivities for nanomeshes with smaller pitches. Ray tracing simulations support the measurement results. We conclude phonon coherence is unimportant for thermal transport in silicon nanomeshes with periodicities of 100 nm and higher and temperatures above 14 K, and phonon backscattering, as manifested in the classical size effect, is responsible for the thermal conductivity reduction. Low thermal conductivities in nanomeshes have been attributed to both wave-like and particle-like behaviour of phonons. Here, the authors use periodicity-controlled silicon nanomeshes to show that the particle backscattering effect dominates for periodicities above 100 nm and temperatures above 14 K. |
| Databáze: | OpenAIRE |
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