Preparation and thermoelectric properties of Bi2Te3-Bi2Se3 solid solutions

Bi 2 Te 3−y Se y (y = 0.0 − 0.6) solid solutions were prepared by encapsulated melting and hot pressing. The lattice constants decreased linearly with increasing Se content, which confirmed the successful formation of the Bi 2 Te 3−y Se y solid solutions. All specimens exhibited n-type conduction in the measured temperature range (323–523 K) and slightly decreased electrical conductivities with increasing temperature. By substituting Se for Te, the Seebeck coefficients were increased, but the electrical and thermal conductivities were reduced: consequently, the dimensionless figures of merit were improved. The highest ZT was obtained as 0.56 at 323 K for Bi 2 Te 2.85 Se 0.15 and as 0.60 at 423 K for Bi 2 Te 2.4 Se 0.6 .