Abstract
We investigate a new application of germanium tin (Ge1−xSnx) binary alloy thin films to realize energy harvesting of low-grade heat to electricity, i.e., thin-film thermoelectric generator (TEG). To clarify the potential of Ge1−xSnx for the TEG application experimentally, it needs to choose high-resistivity wafers as the substrate for the Ge1−xSnx growth to isolate electrically from the substrates. Specifically, this paper conducts crystal growths of Ge1−xSnx on FZ-Si, semi-insulating GaAs, and InP substrates. The impacts of Sn content and crystallographic tilt in the Ge1−xSnx on the thermal conductivity will be discussed experimentally and theoretically. We also show the scaling merit of the device sizes in the power density.