High temperature charge and thermal transport properties of the n-type thermoelectric material PbSe.
- Materials Science Division
We present a detailed study of the charge transport, infrared optical reflectivity, and thermal transport properties of n-type PbSe crystals. A strong scattering, mobility-limiting mechanism was revealed to be at play at temperatures above 500 K. The mechanism is indicative of complex electron-phonon interactions that cannot be explained by conventional acoustic phonon scattering alone. We applied the first-order nonparabolicity approximation to extract the density-of-states effective mass as a function of doping both at room temperature and at 700 K. The results are compared to those of a parabolic band model and in light of doping-dependent studies of the infrared optical reflectivity. The thermal conductivity behavior as a function of temperature shows a strong deviation from the expected Debye-Peierls high-temperature behavior (umklapp dominated) indicating an additional heat-carrying channel, which we associate with optical phonon excitations. The correlation of the thermal conductivity observations to the high-temperature carrier mobility behavior is discussed. The thermoelectric figure of merit exhibits a promising value of {approx} 0.8 at 700 K at {approx} 1.5 x 10{sup 19} cm{sup -3}.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1033485
- Report Number(s):
- ANL/MSD/JA-71500; TRN: US201202%%790
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 84, Issue 15; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
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