Thermoelectric properties of p-type (Bi2Te3)x(Sb2Te3)1−x crystals prepared via zone melting

In the present study, p-type (Bi2Te3)x(Sb2Te3)1−x crystals with various chemical compositions (x=0, 0.05, 0.10, 0.16, 0.20, 0.24 and 0.26) were fabricated through the zone melting method. Thermoelectric properties, including Seebeck coefficient (α), electrical conductivity (σ) and thermal conductivity (κ), were measured in the temperature range of 300-500 K. The influence of the variations of Bi2Te3 content (x) on the thermoelectric properties was studied. The increase of Bi2Te3 content (x) caused a decrease in hole concentration and thus a decrease of σ and an increase of α. The maximum figure of merit (ZT=α2σT/κ) of 1.14 was obtained at about 350 K for the composition of 24% Bi2Te3-76% Sb2Te3 with 3 wt% excess Te.