Abstract

Thermoelectric properties of composite thin films with higher manganese silicide (MnSi_1.7) and silicon (Si) were investigated together with textures and crystal structures. The MnSi_1.7-based thin films were fabricated from multilayers of manganese and silicon by post annealing using planar coupling reactions in the interfaces between the manganese and silicon layers. Moreover, to improve the morphology of the films, the layer thicknesses were changed. As a consequence, smooth and voidless thin films consisting of crystallized MnSi_1.7 were successfully obtained by solid-phase reactions when the thickness of the manganese layer was less than 2 nm. The resistivity of the thin films was reduced about 30% by decreasing the initial manganese thickness when the Si/Mn composition ratio was 2.1. In addition, the Seebeck coefficient was increased to 225 μV/K at 390°C, which is close to the maximum in MnSi_1.7-based compounds, by controlling annealing temperature and annealing time.