| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Outline of Final Research Achievements |
A measurement technique of quasi-ballistic thermal transport in tens of nanometers has been developed by using time-domain thermoreflectance of gold nano-islands. The suppressed apparent thermal conductivity of transparent substrates (fused quartz, crystal quartz, and sapphire) due to quasiballistic thermal transport is obtained through the transient temperature change of the gold nanoislands formed on the substrate surface, and the size effect of thermal conductivity in the range of tens of nanometers is quantified by varying the gold nano-island sizes. Furthermore, characteristic phonon mean free paths of the substrates were obtained by fitting the measured size effect with a solution of a Boltzmann transport equation. The results identify that the size-effect of amorphous fused quartz at room temperature becomes significant when the size is reduced below 60 nm.
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