Structure and thermoelectric properties of binary and Fe-doped iridium silicide thin films

Abstract

The structure-formation process and thermoelectric properties of binary and Fe-doped IrxSi1−x (0.30 ≤ x ≤ 0.41) thin films were investigated. The films were prepared by means of physical vapor deposition techniques, in particular by magnetron co-sputtering and electron beam co-evaporation. The amount of Fe dopant varied between 0 and 5 at.%. The phase-formation process depends on the volume fractions of the major components Ir and Si, whereas the small concentrations of dopant did not change the sequence of the crystalline phases formed. On the other hand, the thermoelectric transport properties correlate strongly with both the structure-formation process and the chemical composition of the films. Fe-doped iridium silicide films with useful thermoelectric power factors were successfully obtained by both magnetron co-sputtering and electron beam co-evaporation. A maximum thermoelectric power factor of 8.5 μW/(K2 cm) at 1200 K was observed for evaporated layers with thechemical composition Ir0.35Si0.63Fe0.02.