High thermoelectric figure of merit of Mg_2Si_(0.55)Sn_(0.4)Ge_(0.05) materials iopei with Bi and Sb

摘要

Thermoelectric properties of new Bi- and Sb-doped Mg_2Si_(0.55)Sn_(0.4)Ge_(0.05) compounds prepared by powder methods were studied in the temperature range 300-823 K. The materials exhibited compositional inhomogeneites consisting of Sn-rich and Sn-poor areas. Doping with Bi or Sb had a very strong influence on the thermoelectric properties. A high figure of merit was obtained, with a value ~1.4 for Bi members and ~1.2 for Sb members at high temperatures. These values are the highest reported on this system.