[C-9] Thermoelectric Devices

[C-9-07] Grain Shape Dependence of Thermal Conductivity of Silicon Polycrystalline Nanostructure

〇Riku Tomabechi¹, Ryusei Taniguchi¹, Takuma Hori¹ (1. Tokyo Univ. of Agriculture and Tech. (Japan))

Presentation style: On-site (in-person)

https://doi.org/10.7567/SSDM.2022.C-9-07

Thermoelectric device can convert thermal energy into electrical one. Decreasing thermal conductivity of the material is theoretically known to be necessary for improving the conversion efficiency. Nanostructuring of materials can impede lattice vibration (phonon) transport and thus it is effective for decreasing thermal conductivity of semiconductors. In this study, the influence of grain shape of polycrystalline nanostructure on its thermal conductivity is evaluated by numerical analysis. Our phonon transport simulations reveal that the mean free path of phonons in nanostructures of uniform grain shape has correlation with ratio of the grain volume to its surface area. This tendency is reasonable since scattering frequency between phonons and grain boundaries decreases with smaller surface area.