2005 年 46 巻 5 号 p. 959-962
P-type (Bi2Te3)x(Sb2Te3)1−x thermoelectric materials with various chemical compositions (x=0.16, 0.20 and 0.24) were fabricated through the zone melting (ZM) method and spark plasma sintering (SPS) technique. The dimensionless figure of merit (ZT=α2σT⁄κ) of the zone-melted crystals increased with increasing the Bi2Te3 content (x). Compared to those of the zone-melted crystals with the same chemical composition, further enhancement by 108–115% in the ZT values was obtained through a combination of ZM and SPS techniques. As a result, the optimal figure of merit reached 1.22 at about 350 K for the composition of 24%Bi2Te3–76%Sb2Te3 with 3 mass% excess Te. The bending strength of the sintered materials was about 65 MPa, which was 5–7 times higher than that of the zone-melted crystals.