Superior power generation capacity of GeSn over Si demonstrated in cavity-free thermoelectric device architecture


 The performance of a thermoelectric (TE) generator consisting of Germanium-tin (GeSn) wire has been experimentally found to be higher than that of a TE generator fabricated by Silicone (Si) wire. The TE generators were developed in a cavity-free architecture, where the wires are directly placed on the substrate without forming a cavity space underneath. In the Cavity-free structure, the heat current flows perpendicularly to the substrate and the TE generator is driven by a steep temperature gradient established around the heater inlet. With an identical patterning design, the TE performance of both generators was characterized by varying lengths. The maximum Seebeck coefficient of the generator consisting of GeSn is -277 μV/K and for the Si is -97 μV/K. The GeSn-TE generator has achieved high power factor of 31 μW∙K-2 ∙cm-1 than the Si-TE generator of 12 μW∙K-2 ∙cm-1. The maximum areal power density of the GeSn-TE generator is intrinsically higher than that of the Si-TE generator by approximately 2.5 to 6 times considering the wire thickness difference. The obtained results prefer the superiority of the GeSn-TE generator over the Si-TE generator.