Crystal Structure and Thermoelectric Properties of ReSi_1.75 Based Alloys

Effect of the ternary element of Mo on the crystal structure and thermoelectric properties of ReSi1.75 has been investigated. The crystal structure of Mo-containing ReSi1.75 has shear structure up to 1.5 at%, the structure changes into adaptive structure at larger Mo contents. The concentration of Si vacancies estimated from the crystal structures determined decreases with increasing Mo content. Thermoelectric properties of Mo-containing ReSi1.75 indicate that the character changes from p- to n-type semiconductor upon alloying with Mo, which is explained by the decrease in Si vacancy concentration.