Thermoelectric Properties of Amorphous Ge/Au and Si/Au Thin Films

Abstract

Thermoelectric Properties of Ge/Au and Si/Au thin films have been measured as functions of Au concentration and annealing cycles. Ge/Au and Si/Au thin films were prepared by the alternating deposition of Ge or Si and Au in the ultra-high vacuum chamber. In the Ge/Au thin films, the annealing cycles dependence of electrical resistivity decreases as Au concentration increases. The Ge/Au thin films both of 0 and 5 mass % Au have large thermoelectric power. High Au concentration samples are recrystallized even in the heating phase of 1st annealing cycle. From the difference of the atomic radius, Au should be the origin of amorphous phase. The best condition for high thermoelectric properties must be in low Au concentration. For the electrical resistivity of Si/Au thin films, there are almost no dependence of the annealing cycles. Au mainly plays the role of carrier source for the change of the electrical resistivity with Au concentration. We can conclude that the mechanism of the anomalously large thermoelectric power of Si-Ge-Au thin films comes out from the amorphous phase of Si and Ge.