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Title: Enhancing the thermoelectric figure of merit through the reduction of bipolar thermal conductivity with heterostructure barriers

In this paper, we present theoretically that the thermoelectric figure of merit for a semiconductor material with a small band gap can be significantly enhanced near the intrinsic doping regime at high temperatures via the suppression of bipolar thermal conductivity when the minority carriers are selectively blocked by heterostructure barriers. This scheme is particularly effective in nanostructured materials where the lattice thermal conductivity is lowered by increased phonon scatterings at the boundaries, so that the electronic thermal conductivity including the bipolar term is limiting the figure of merit zT. We show that zT can be enhanced to above 3 for p-type PbTe, and above 2 for n-type PbTe at 900 K with minority carrier blocking, when the lattice thermal conductivity is as low as 0.3 W/m K.
Authors:
;  [1]
  1. Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)
Publication Date:
OSTI Identifier:
22314490
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GRADED BAND GAPS; LEAD TELLURIDES; PERFORMANCE; SEMICONDUCTOR MATERIALS; THERMAL CONDUCTIVITY; THERMOELECTRIC PROPERTIES