Fabrication of amorphous Si/Au/Ge/Au 4 layers interval superlattice thin film for thermoelectric materials

The amorphous Si-Ge-Au thin films show the extremely high thermoelectric properties. But reproducibility of the samples was not enough, because Au dopant was evaporated from dissolved Ge-Au ingot. In order to improve this problem, the thin film samples were deposited by ultra high vacuum evaporation system with three individual controlled sources, Si, Ge and Au. The samples were prepared of Si/Au/Ge/Au 4 layers as one period of 10 nm. And all the samples have 30 periods. Composition and thermoelectric properties of the samples were measured. The compositions of the thin films were measured by X-ray fluorescent analysis and that was consistent with intended value. The maximum value of thermoelectric power was ~10^-3 V/K at room temperature. By this sample preparation procedure, we have succeeded to make thin films with accurate dopant composition.