Influence of an interlayer on thermoelectric power factor of HMS film on quartz substrate

Abstract

The influence of an AlO x oxide or Si interlayer on the thermoelectric power factor of the higher manganese silicide (HMS, MnSi y, y = 1.73–1.75) film deposited on quartz substrate is investigated. The HMS film and the interlayer are prepared on quartz substrate by magnetron sputtering of MnSi 2, Al , Si and Si : B (1 at.% B content) targets. It is found that the metallic phase MnSi is present in the semiconducting HMS film without an interlayer, resulting in a lower Seebeck coefficient, 0.160 mV/K, but not a lower electrical resistivity, 0.021 Ω ⋅cm at 683 K. The thermoelectric power factor is only 122 × 10-6 W/mK2 at 683 K. On the other hand, the metallic phase MnSi disappears and the Seebeck coefficient restores to its high value after using the AlO x oxide or Si interlayer. Besides, the electrical resistivity decreases by using the AlO x oxide or Si : B interlayer. The HMS film with an Si : B interlayer has the highest Seebeck coefficient, 0.247 mV/K, and the lowest electrical resistivity, 0.011 Ω ⋅cm, at 683 K. Thus, the thermoelectric power factor is enhanced and can reach 555 × 10-6 W/mK2 at 683 K.