MA-PCSプロセスによるターゲットを用いた(Bi₂Te₃)_0.25(Sb₂Te₃)_0.75熱電薄膜の作製

抄録

A p-type thermoelectric film of (Bi₂Te₃)_0.25(Sb₂Te₃)_0.75 was fabricated by radio frequency sputtering. The target for the sputtering was prepared by mechanical alloying (MA) and pulsed current sintering (PCS) process. The single phase of Bi_0.5Sb_1.5Te₃ was obtained by planetary ball milling Bi powder, Te powder and Sb powder for 36ks. The obtained powder was consolidated by PCS into the cylindrical target of 50 mm in diameter and 4mm in thickness at 643 K under a pressure of 13 MPa. The sintered body consisted of Bi_0.5Sb_1.5Te₃ without cracks. The sintered Bi_0.5Sb_1.5Te₃ was joined to Cu backing plate with In for an insertion by PCS process. The thin film of (Bi₂Te₃)_0.25(Sb₂Te₃)_0.75 was fabricated on a polyimide substrate by RF sputtering. The thickness of this thin film was about 15-20μm. This film was amorphous state and crystallized at about 520 K. The performance of this p-type thermoelectric film after the crystallization were 2.0mV in voltage and 2.9μA in current at 20 K of the difference between heating side temperature 353 K and cooling side temperature 333 K.