Thermoelectric properties of the p-type Bi2Te3–Sb2Te3–Sb2Se3 alloys fabricated by mechanical alloying and hot pressing Original Research Article

The p-type (100−x)% Bi2Te3–x% Sb2Te3 (75≤x≤85) and 20% Bi2Te3–(80−y)% Sb2Te3–y% Sb2Se3 (0≤y≤7) alloys were fabricated by mechanical alloying and hot pressing, and their thermoelectric properties were characterized. Among the hot-pressed (100−x)% Bi2Te3–x% Sb2Te3 alloys, the 20% Bi2Te3–80% Sb2Te3 alloy exhibited a maximum figure-of-merit of 3.05×10−3/K. The Seebeck coefficient and the electrical resistivity of the hot-pressed 20% Bi2Te3–(80−y)% Sb2Te3–y% Sb2Se3 alloys increased with increasing the Sb2Se3 content due to the reduction of the hole concentration. The figure-of-merit of the hot-pressed 20% Bi2Te3–(80−y)% Sb2Te3–y% Sb2Se3 alloys decreased from 3.05×10−3/K to 2.5×10−3/K with increasing the Sb2Se3 content up to 7 mol%, because the increment of the electrical resistivity was much larger than the decrement of the thermal conductivity and the increment of the Seebeck coefficient.