Variation des vitesses de propagation des ultrasons dans le silicium monocristallin entre 25° et 830°C

Ezz-el-Arab, M. A.; Galperin, Bella L.; Brielles, J; Vodar, B.

doi:10.1016/0038-1098(68)90163-4

Cited by 21 publications

(2 citation statements)

References 6 publications

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“…Twenty years ago, a concept of quantum confinement was proposed by Hicks and Dresselhaus for decoupling these three parameters, particularly in low‐dimensional materials . During the subsequent years, many recent efforts have been taken to decouple these parameters for enhancing the power factor ( S 2 σ) by band engineering approaches including band convergence, band nestification, and band distortion …”

Section: Introductionmentioning

confidence: 99%

Manipulation of Phonon Transport in Thermoelectrics

2018

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For several decades, thermoelectric advancements have largely relied on the reduction of lattice thermal conductivity (κ ). According to the Boltzmann transport theory of phonons, κ mainly depends on the specific heat, the velocity, and the scattering of phonons. Intensifying the scattering rate of phonons is the focus for reducing the lattice thermal conductivity. Effective scattering sources include 0D point defects, 1D dislocations, and 2D interfaces, each of which has a particular range of frequencies where phonon scattering is most effective. Because acoustic phonons are generally the main contributors to κ due to their much higher velocities compared to optical phonons, many low-κ thermoelectrics rely on crystal structure complexity leading to a small fraction of acoustic phonons and/or weak chemical bonds enabling an overall low phonon propagation velocity. While these thermal strategies are successful for advancing thermoelectrics, the principles used can be integrated with approaches such as band engineering to improve the electronic properties, which can promote this energy technology from niche applications into the mainstream.

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Section: Introductionmentioning

confidence: 99%

Manipulation of Phonon Transport in Thermoelectrics

2018

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“…The frequency shift per degree is 0.24 MHz.K -1 or Ω.4.10 -5 K -1 is in agreement with a simple Fabry-Perrot model Ω=v/2w with v, the sound velocity, and w, the waveguide width, for the phonon resonance. Thereby we take into account the thermal dependency of the sound velocity Δ v / ΔT = v .5.10 -5 as found in literature [5].…”

Section: Resultsmentioning

confidence: 99%