Enhancement of the Thermoelectric Performance of Bi_(0.4)Sb_(1.6)Te_3 Alloys by In and Ga Doping

Abstract

We report an enhancement of the thermoelectric figure of merit in polycrystalline In- and Ga-doped Bi_(0.4)Sb_(1.6)Te_3 compounds. Via the controlled doping of In or Ga, the lattice thermal conductivity was effectively reduced by strong point-defect phonon scattering while the power factor was not significantly changed due to the similarity of the density of states near the valence-band maximum between undoped and In- or Ga-doped compositions. An enhanced ZT of 1.2 at 320 K was obtained in 0.5 at.% In-doped Bi_(0.4)Sb_(1.6)Te_3 compound by these synergetic effects.

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