Microstructure and thermoelectric properties of p-type Bi2Te3-Sb2Te3 alloys produced by rapid solidification and spark plasma sintering

P-type Te-doped Bi2Te3-Sb2Te3 compounds were prepared using rapid solidification and spark plasma sintering (SPS) techniques. The microstructure and thermoelectric properties were evaluated as a function of the SPS temperature. The phase distribution was characterized by X-ray diffraction (XRD) and examined by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) area scanning. The thermoelectric properties were evaluated by a combination of thermal conductivity, electrical resistivity and Seebeck coefficient. The solidified powders consisted of homogeneous thermoelectric phase. As the SPS temperature increases, the microstructure become coarsen, resulting in the reduction of hardness. The thermoelectric figure of merit measured to be the maximum (3.05 x 10-3/oC) at the SPS temperature of 430 oC.