Work

Decreasing of the thermal conductivity of Si nanopillar/SiGe composite films investigated by using a piezoelectric photothermal spectroscopy

Year: 2020

Type: article

Abstract: To investigate the decrease of thermal conductivity ( κ ) of nanoscale Si materials, we conducted the piezoelectric photothermal (PPT) method for the highly periodic Si nanopillar arrays embedded in Si 0.7 Ge 0.3 . 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, κ was estimated from the comparison with the model analysis based on the one-dimensional multilayer thermal diffusion equation. The estimated κ was 0.19 ± 0.07 W m –1 K, in the parallel to the nanopillars direction. Since the considerable decrease of κ was confirmed from the non-radiative recombination point of view, we found the present non-destructive PPT method is very useful to estimate κ in the nanostructured devices for the thermoelectric application.

Source: Japanese Journal of Applied Physics

DOI: 10.35848/1347-4065/ab82a6

Authors: Tomoki Harada, Tsubasa Aki, Daisuke Ohori, Seiji Samukawa, Tetsuo Ikari, Atsuhiko Fukuyama

Institutions: University of Miyazaki, Tohoku University, Institute of Fluid Science, Tohoku University, Advanced Institute for Materials Research, Tohoku University

Language: English

Topic: Thermal properties of materials

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funders: Japan Society for the Promotion of Science, Institute of Fluid Science, Tohoku University

Awards: Predominance of quantum well structure for solar cell application from a non-radiative electron transition loss point of view, Development of the non-destructive and 3-dimentional profile investigation of the non-radiative recombination in the nano-structure inserted solar cells