Thermoelectric (BaxSr1-x)Si2 films prepared by sputtering method over the barium solubility limit

Abstract

In this work, (BaxSr1-x)Si2 thin films were prepared by the co-sputtering method at various deposition temperatures. The constituent phase of the films primarily depended on the deposition temperature and the composition x. The composition to make a solid solution was expanded by lowering the deposition temperature, compared to that of bulk-sintered bodies. Further lowering the deposition temperature produced a metastable phase, which was a layered structure (trigonal, EuGe2-type structure), with a low thermoelectric power factor. Substitution with Ba led to an increase in the temperature showing the highest power factor. The samples with Ba concentrations over 17% showed the maximum power factor around room temperature.