Structural effects on the performance of microfabricated in-plane π -type thermoelectric devices composed of p-type Mg2Sn0.8Ge0.2 and n-type Bi layers

Abstract

Miniaturized in-plane π-type thermoelectric devices composed of p-type Mg2Sn0.8Ge0.2 and n-type Bi layers were prepared by microfabrication techniques. Structural effects on thermoelectric device performance need to be evaluated and optimized to improve device performance and operation. In this study, a rational analysis of the correction of the open-circuit output voltages, output powers, and output power densities by using effective temperature differences was performed, and the effects of device geometries (e.g., the number of π junctions and the cross-sectional area ratio between p- and n-type layers) were determined by comparing different types of in-plane π-type thermoelectric devices. The results revealed that it is crucial to consider the heat transfer loss caused by thermal contact effects in the device and to optimize the structural geometries of the device. Proper structural trends and the effects of the number of p–n pairs on the device performance were observed, which indicated the reasonable device operation of microfabricated in-plane π-type thermoelectric devices.