Characterization of thermoelectric properties of layers obtained by pulsed magnetron sputtering

The pulsed magnetron sputtering technique was applied for the preparation of layers of Bi2Te3 and Sb2Te3. Target materials were synthesized in evacuated quartz ampoules by melting elemental powders mixed in stoichiometric proportions. The structure and microstructure of targets and prepared films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. Thermoelectric properties were defined by the Seebeck coefficient and electrical conductivity measurements in the temperature range 320-430 K. The layers were deposited at various powers (0.09-0.20 kW) and currents (0.07-0.16 A) at an argon pressure of about 3.0 Pa. The efficiencies of thermoelectric power obtained for bismuth telluride and antimony telluride were 2-4 x 10(-4) and 2-6 x 10(-3) W K-2 m(-1), respectively. The synthesized materials were used for the fabrication of thermoelectric couples with Bi2Te3 as the n-type material and Sb2Te3 as the p-type material. The thermocouples were annealed under vacuum to obtain optimum thermoelectric properties. The Seebeck coefficient of thermocouples was evaluated by a Seebeck scanning microprobe [Platzek D, Karpinski G, Stewie C, Muchilo D, Muller E. Proceedings of the second European conference on thermoelectrics, Poland, Cracow, September 15-17, 2004]. (C) 2008 Elsevier Ltd. All rights reserved.