Thermoelectric properties of CoSb3 thin films prepared by ion-beam sputtering

In order to synthesize thin films of a CoSb3 compound, thin Co/Sb multi-lay ered films were prepared by an ion-beam sputtering method, and annealed in a temperature range between 673 and 773 K for 1 to 3 h in a vacuum atmosphe re. The effects of both chemical composition and annealing conditions on th e CoSb3 phase evolution were evaluated by X-ray diffraction and transmissio n electron microscopy. The thermoelectric properties of the annealed films were studied at elevated temperatures. The results obtained are summarized as follows: In a rather wide composition range such as 70 to 85 at% Sb, thi n films consisting of a CoSb3 single phase were successively synthesized. T he CoSb3 films showed a p-type semiconducting character, and their thermoel ectric transport properties were found to be nearly closed to those of bulk materials reported so far. It was also found that the grain size, electric al conductivity and Seebeck coefficient of the CoSb3 films were dependent o n their chemical composition after annealing.