Thermoelectric and transport properties of mechanically-alloyed Bi2Te3-y Se y solid solutions

Bi2Te3-y Se (y) (y = 0 - 0.6) solid solutions were prepared by using mechanical alloying and hot pressing. The lattice constants decreased with increasing Se content, which revealed the successful formation of solid solutions by using a planetary mill. The relative densities of hot-pressed specimens were higher than 96%. All specimens indicated n-type conductions in the measuring temperature range from 323 K to 523 K, and the electrical conductivity slightly decreased with increasing temperature. The Seebeck coefficient increased with increasing Se content, and the electrical and the thermal conductivities decreased; thus, the dimensionless figure of merit was improved. A maximum dimensionless figure of merit of 0.76 was obtained at 473 K for Bi2Te2.55Se0.45.