Defect structure of Sb2−xFexTe3 single crystals

Single crystals of Sb2−xFexTe3 (cFe=0–9.5×1019 cm−3) were prepared by Bridgman method. The interpretation of the reflection spectra in plasma resonance region indicates that Fe increases the concentration of holes (acceptor) and each Fe atom incorporated in Sb2Te3 structure liberates 0.4–0.5 hole. Observed effect is elucidated by means of point defect model. According to the model Fe atoms enter the structure and form uncharged substitutional defects image. Since this defect cannot affect the free-carrier concentration directly, we assume an interaction of the entering Fe-atoms with natives defects leading to a rise in the concentration of antisite defects image, to a decrease of image concentration, and to an increase in the concentration of holes.