Investigation of electrical transport properties of Bi_0.5Sb_1.5Te_2.7Se_0.3 alloys prepared by high-pressure method

The quaternary Bi _0.5 Sb _1.5 Te _2.7 Se _0.3 alloys have been successfully synthesized within 25 min by high-pressure method. The pressure-dependent electrical transport properties of the as-prepared Bi _0.5 Sb _1.5 Te _2.7 Se _0.3 alloys are carefully investigated at room temperature. The measurement results indicate that the electrical resistivity and the Seebeck coefficient reveal a strong correlation with the increase of synthesis pressure. The carrier concentration and mobility are modulated effectively due to the effects of synthesis pressure and composition, leading to an improvement in the power factor of Bi _0.5 Sb _1.5 Te _2.7 Se _0.3. These results suggest that the utilization of pressure during the synthesis process provides an effective and controllable strategy to optimize the electrical transport properties of the ( Bi , Sb )₂( Te , Se )₃ alloys.