Plasticity of Bi(2)Te(3)-family thermoelectric crystals.

The exceptional plasticity discovered most recently in defective Bi(2)Te(3) bulk crystal inspires the great interest on investigating the plasticity of other Bi(2)Te(3)-family bulk crystals. In this work, Bi(2)Se(3), Sb(2)Te(3), and their solid solutions with Bi(2)Te(3) are grown by the temperature gradient method to comprehensively clarify the relationship among chemical composition, native defect, microstructure, and plasticity of Bi(2)Te(3)-family compounds. Compared with Bi(2)Te(3) bulk crystal, Bi(2)Se(3) and Sb(2)Te(3) bulk crystals exhibit poorer plasticity at room temperature. The origin is attributed to the lack of substantial antisite defects in Bi(2)Se(3) and Sb(2)Te(3) alike that in Bi(2)Te(3), which impedes the formation of the high-density, diverse microstructures. Alloying either Se or Sb in Bi(2)Te(3) modifies the native defects and microstructures and thus changes plasticity and thermoelectric performance. Finally, the composition range for the Bi(2)(Te,Se)(3) and (Bi,Sb)(2)Te(3) bulk crystals that simultaneously possess exceptional plasticity (maximum bending strain >10%) and thermoelectric performance is determined.