The Effects of Thermoelectric Film Thickness on Performance of In-Plane Thermoelectric Modules

Abstract

We fabricated in-plane thermoelectric modules (4 mm × 4 mm) on a 4-μm-thick substrate using a vacuum deposition process through a shadow mask. In this study, a thermoelectric p–n pair was established using multilayered films of p and n thermoelectric thin films and an insulator film with a hole at the center. The output power was 58 nW at 443 K using the multilayered microgenerator. We discuss the effects of device thickness on the efficiency of the microgenerator to increase the output electric power. We evaluated the output power of the in-plane thermoelectric generator with a substrate using a one-dimensional heat conduction model, and it was found to depend on the thickness of the thermoelectric film. If the thermoelectric film is very thin, the power factor is more important than the nondimensional figure of merit, ZT. Metal thin films with high power factor are more efficient than semiconductors with low power factors even though their thermal conductivities are high. When the thermoelectric thin film is thick, ZT should be higher for larger output power of the device.