Library Subscription: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EFFECTS OF ELECTRON-PHONON INTERACTIONS ON LATTICE THERMAL CONDUCTIVITY OF DOPED SNSE

Get access (open in a dialog) DOI: 10.1615/IHTC16.cms.022971
pages 1907-1915

Abstract

Tin selenide (SnSe) owns the highest figure of merit ZT value among the state-of-the-art thermoelectric materials mainly for its extremely low thermal conductivity. Recent investigations show that heavily doped SnSe achieves high ZT over the entire moderate temperature range. Phonons play an important role in the heat dissipation of SnSe. Electrons will have significant effects on phonons transport, especially for heavily doped semiconductors. Therefore, understanding the electron-phonon coupling contribution to heat transfer of SnSe is critical to explain experimental results and real application phenomenon. In this work, the effect of electron phonon interactions on lattice thermal conductivity of doped SnSe is comprehensively investigated from the atomic level by performing first-principles calculations. We find that electron-phonon coupling has little effects on the phonon thermal conductivity of lightly doped SnSe, which could be ignored in the calculation. However, the effect would be very strong for both heavily hole- and electron-doped SnSe when the doping concentration is larger than 1020 cm-3. The phonon-phonon thermal conductivity can be reduced by 14.7% and 30.4% on the b-axis for hole and electron doping at the doping concentration of 1021 cm-3 in the room temperature, respectively. Temperature has significant effect on phonon-phonon scattering, but the electron-phonon scattering is insensitive to it. Electron-phonon scattering rate has stronger effects on the lattice thermal conductivity in low temperature range due to the smaller phonon-phonon scattering rate. Besides, the mean free paths of phonons which transport heat become smaller when the electron phonon interactions are considered. This work attempts to investigate the mechanism of thermal transport beyond intrinsic phonon-phonon interaction for both electron- and hole-doped SnSe, with comprehensive understanding the singularly low thermal conductivity.