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Universal phonon mean free path spectra in crystalline semiconductors at high temperature.

ABSTRACT: Thermal conductivity in non-metallic crystalline materials results from cumulative contributions of phonons that have a broad range of mean free paths. Here we use high frequency surface temperature modulation that generates non-diffusive phonon transport to probe the phonon mean free path spectra of GaAs, GaN, AlN, and 4H-SiC at temperatures near 80?K, 150?K, 300?K, and 400?K. We find that phonons with MFPs greater than 230 ± 120?nm, 1000 ± 200?nm, 2500 ± 800?nm, and 4200 ± 850?nm contribute 50% of the bulk thermal conductivity of GaAs, GaN, AlN, and 4H-SiC near room temperature. By non-dimensionalizing the data based on Umklapp scattering rates of phonons, we identified a universal phonon mean free path spectrum in small unit cell crystalline semiconductors at high temperature.

SUBMITTER: Freedman JP

PROVIDER: S-EPMC3797423 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Universal phonon mean free path spectra in crystalline semiconductors at high temperature.

Freedman Justin P JP Leach Jacob H JH Preble Edward A EA Sitar Zlatko Z Davis Robert F RF Malen Jonathan A JA

Scientific reports 20131016

Thermal conductivity in non-metallic crystalline materials results from cumulative contributions of phonons that have a broad range of mean free paths. Here we use high frequency surface temperature modulation that generates non-diffusive phonon transport to probe the phonon mean free path spectra of GaAs, GaN, AlN, and 4H-SiC at temperatures near 80 K, 150 K, 300 K, and 400 K. We find that phonons with MFPs greater than 230 ± 120 nm, 1000 ± 200 nm, 2500 ± 800 nm, and 4200 ± 850 nm contribute 50 ...[more]

PMID: 24129328

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