Thermoelectric property studies on thallium-doped lead telluride prepared by ball milling and hot pressing

Thallium doping into lead telluride has been demonstrated to increase the dimensionless thermoelectric figure-of-merit (ZT) by enhancing Seebeck coefficient due to the creation of resonant states close to Fermi level without affecting the thermal conductivity. However, the process is tedious, energy consuming, and small in quantities since it involves melting, slow cooling for crystal growth, long time annealing, post-crushing and hot pressing. Here we show that a similar ZT value about 1.3 at 400 degrees C is achieved on bulk samples with grain sizes of 3-7 mu m by ball milling a mixture of elemental thallium, lead, and tellurium and then hot pressing the ball milled nanopowders. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3452323]