Fabrication and thermoelectric properties of crystal-aligned nano-structured Bi2Te3

With a view to experimental demonstration for an improved thermoelectric performance, a slip casting method under high magnetic field for uni-directionally aligned crystals has been investigated. The sintered body of Bi2Te3 powder, its size between 300 and 500 nm, green-bodied under 6 T magnetic field showed a 33% variation in the fraction of the directionally aligned crystals. According to increasing this fraction, electrical resistivity was reduced with keeping thermal conductivity and Seebeck coefficient unchanged. This could be explained from the fact that the aligned crystals by magnetic field has increased the carrier mobility keeping carrier concentration unchanged.

Research highlights
► In the present study, a c-axis aligned nanostructured Bi2Te3 is successfully prepared via a slip-casting method under a 6-T magnetic field and their thermoelectric properties are investigated.
► The grain size of nanostructred Bi2Te3 is in between 400 and 500 nm, no difference originated to the magnetic field treatment.
► The 6-T magnetic field played a role in aligning crystals to [0 0 l] planes.