[21p-P09-1~10] 9.4 Thermoelectric conversion

[21p-P09-2] Evaluation of phonon mean free paths of Si single crystals with different carrier concentrations and estimation of Seebeck coefficients contributed by phonon drag effect

〇Masataka Hase¹, Daiki Tanisawa¹, Naoto Kudo², Sho Nagata², Tuyoshi Nishi², Shugo Miyake³, Masayuki Takashiri¹ (1.Graduate School of Engineering, Tokai Univ., 2.Graduate School of Science and Technology, Ibaraki Univ., 3.Kobe City National College of Technology)

Keywords:Silicon, Phonon drag effect, Phonon mean free path

In this study, we derived phonon mean free path (MFP) in Si single crystals with different carrier concentrations using the nanoindentation method and evaluated the Seebeck coefficient S_p due to the phonon drag effect. In general, S_p increases with lower carrier concentration, but the present results show the opposite behavior to the theoretical one. This is due to the fact that the MFP in this study are more dependent on short-wavelength phonons, suggesting that the effect of the phonon drag effect may improve with this decrease.