DEVELOPMENT OF A NEW PROCESS FOR ACHIEVING OPTIMAL ANISOTROPIC TEXTURE VALUE IN GeTe+7%Bi₂Te₃ ALLOY

Germanium telluride based alloys are known as appropriate candidates for 𝑝-type legs in thermoelectric applications at 300–500^∘C, exhibiting high dimensionless thermoelectric figure of merit. For obtaining optimal thermoelectric properties, it is necessary to dope GeTe with donor type electroactive impurities, in order to reduce the hole concentration. Bi₂Te₃ as a donor exhibit an anisotropic thermoelectric properties due to the atomic arrangement. GeTe+7% Bi₂Te₃ ingot was synthesized by rocking furnace, pulverized to a powder and sieved to several grain size. 60 to 80 mesh showed the maximal of 12% texture anisotropy value and was chosen as the working powder particles size for this research. The sieved process followed by hot pressing yielded up to 20% anisotropy texture value in perpendicular to the pressing direction. Other GeTe+7%BiTe flakes obtained by melt spinning process achieved 40% anisotropy texture.