Single crystal of (Sb 0.75 Bi 0.25) 2-x FexTe3 and Sb 1.5 Bi 0.5 Fe x Te3 (x = 0,0 - 0.015) have been prepared and characterized by the measurments of X-ray diffraction, reflectance in the plasma resonance frequency region, Hall coefficient RH (B // c), electrical conductivity sigma +, and Seebeck coeficient alpha (delta T + c). It was found that Fe atoms in the crystal structure of Sb 1.5 Bi 0.5 Te3 behave like acceptors: the observed increase in the hole concentration with and increase in the hole concentration with an increase in the incorporated Fe content is explained by the formation of substatantial defects of Fe' Sb and Fe' Bi in the crystal lattice of the crystals studied. The incorporation of Fe atoms into the Sb 1.5 Bi 0.5 Te3 lattice leads also to a decrease in the power factor sigma alpha 2 of the crystals.
