Effects of crystal-alignment and grain shape on the thermoelectric properties of Bi0.5Sb1.5Te3 alloys

We investigated the thermoelectric properties of sintered Bi0.5Sb1.5Te3 alloys containing grains for their alignment, sizes and shapes. The figure of merit can be improved as the result of lower resistivity by increasing the alignment, which is realized by using the spark plasma sintering method and a strong magnetic field. In addition, making the grains more spherical can improve the thermoelectric efficiency as a result of carrier quantum confinement and enhancement of the band gap energy. (C) 2011 Elsevier B. V. All rights reserved.