TY - JOUR
T1 - Decreasing of the thermal conductivity of Si nanopillar/SiGe composite films investigated by using a piezoelectric photothermal spectroscopy
AU - Harada, Tomoki
AU - Aki, Tsubasa
AU - Ohori, Daisuke
AU - Samukawa, Seiji
AU - Ikari, Tetsuo
AU - Fukuyama, Atsuhiko
N1 - Funding Information:
Part of this work was carried out under the Collaborative Research Project of the Institute of Fluid Science, Tohoku University.
Publisher Copyright:
© 2020 The Japan Society of Applied Physics.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - To investigate the decrease of thermal conductivity (k) of nanoscale Si materials, we conducted the piezoelectric photothermal (PPT) method for the highly periodic Si nanopillar arrays embedded in Si0.7Ge0.3. The PPT is an electrode free method that can measure a heat propagation in the parallel to the nanopillars direction. A distinctive dip was observed in the frequency-dependent PPT signal intensity. By focusing the dip frequency, k was estimated from the comparison with the model analysis based on the one-dimensional multilayer thermal diffusion equation. The estimated k was 0.19 ± 0.07 W m-1 K, in the parallel to the nanopillars direction. Since the considerable decrease of k was confirmed from the non-radiative recombination point of view, we found the present non-destructive PPT method is very useful to estimate k in the nanostructured devices for the thermoelectric application.
AB - To investigate the decrease of thermal conductivity (k) of nanoscale Si materials, we conducted the piezoelectric photothermal (PPT) method for the highly periodic Si nanopillar arrays embedded in Si0.7Ge0.3. The PPT is an electrode free method that can measure a heat propagation in the parallel to the nanopillars direction. A distinctive dip was observed in the frequency-dependent PPT signal intensity. By focusing the dip frequency, k was estimated from the comparison with the model analysis based on the one-dimensional multilayer thermal diffusion equation. The estimated k was 0.19 ± 0.07 W m-1 K, in the parallel to the nanopillars direction. Since the considerable decrease of k was confirmed from the non-radiative recombination point of view, we found the present non-destructive PPT method is very useful to estimate k in the nanostructured devices for the thermoelectric application.
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U2 - 10.35848/1347-4065/ab82a6
DO - 10.35848/1347-4065/ab82a6
M3 - Article
AN - SCOPUS:85084174796
SN - 0021-4922
VL - 59
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
M1 - SKKA08
ER -