Effect of Sn Doping on the Thermoelectric Properties of n-type Bi^sub 2^(Te,Se)^sub 3^ Alloys

Issue Title: 2014 International Conference on Thermoelectrics. Guest Editors: Lasse Rosendahl, Donald Morelli, Jihui Yang, Hiroaki Anno, Matt Beekman, Jan D. Koenig, Xinfeng Tang, James R. Salvador, Bertrand Lenoir, Chunlei Wan, Jeff Sharp, Emmanuel Guilmeau, Hsin Wang, Jing-feng Li, Tie-Jun Zhu, David Singh, Ryoji Funahashi, Yuri Grin, and Wenqing Zhang In the present work, 0.01-0.05wt.% Sn-doped Bi^sub 2^(Te^sub 0.9^Se^sub 0.1^)^sub 3^ alloys were prepared by mechanical deformation followed by hot pressing, and their thermoelectric properties were studied. We observed that the Sn element is a very effective dopant as an acceptor to control the carrier concentration in the n-type Bi^sub 2^(Te^sub 0.9^Se^sub 0.1^)^sub 3^ alloys to optimize their thermoelectric property. The n-type carrier concentration can be controlled from 4.2 × 10^sup 19^/cm^sup 3^ to 2.4 × 10^sup 19^/cm^sup 3^ by 0.05wt.% Sn-doping. While the Seebeck coefficient and the electrical resistivity are both increased with doping, the power factor remains the same. Therefore, we found that the thermoelectric figure-of-merit becomes maximized at 0.75 when the thermal conductivity has a minimum value for the 0.03wt.% Sn-doped sample.