Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane
Abstract
The "textbook" phonon mean free path of heat carrying phonons in silicon at room temperature is ∼40 nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ∼1–10 μm. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.
Additional Information
© 2013 American Physical Society. Received 29 April 2012; published 8 January 2013. This work was supported as part of the S3TEC Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences under Award No. DE-SC0001299/DE-FG02-09ER46577 (experimental setup and data analysis). This work was also partially supported by projects NANOPOWER, Contract No. 256959; TAILPHOX, Contract No. 233883; NANOFUNCTION, Contract No. 257375; ACPHIN, Contract No. FIS2009-150; and AGAUR, 2009-SGR-150. The samples were fabricated using facilities of the ICTS "Integrated Nano and Microfabrication Clean Room" (CSIC-CNM).Attached Files
Published - PhysRevLett.110.025901.pdf
Accepted Version - 1204.4735.pdf
Supplemental Material - supplemental.pdf
Files
Additional details
- Alternative title
- Direct Measurement of Room Temperature Non-diffusive Thermal Transport Over Micron Distances in a Silicon Membrane
- Eprint ID
- 106336
- Resolver ID
- CaltechAUTHORS:20201028-142514455
- Department of Energy (DOE)
- DE-SC0001299
- Department of Energy (DOE)
- DE-FG02-09ER46577
- European Research Council (ERC)
- 256959
- European Research Council (ERC)
- 233883
- European Research Council (ERC)
- 257375
- Ministerio de Economía, Industria y Competitividad (MINECO)
- FIS2009-150
- Generalitat de Catalunya
- 2009-SGR-150
- Created
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2020-10-29Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field