Investigation of interfacial thermal resistance between Bi₂Te₃ thin films and metal electrodes via TDTR

A challenge on promoting thermoelectric application is the low energy conversion efficiency of thermoelectric devices. Reducing the contact thermal resistance of a thermoelectric device can improve efficiency effectively. However, study on interfacial thermal transport is lack due to the difficulty on contact thermal resistance measurement. Herein, a study on contact thermal resistance between thermoelectric and electrode materials was reported. We prepared various heterostructures of Bi₂Te₃–Cu and Bi₂Te₃–Ni via magnetron sputtering, and measured the contact thermal resistance using a time-domain thermoreflectance technique. Our results show that the contact thermal resistance is affected by both chemical and physical properties of interface. The chemical and physical stability of interfaces, the surface roughness and porosity of films, as well as electrical properties of Bi₂Te₃, are all related to the contact thermal resistance. The contact thermal resistance of Bi₂Te₃–Ni prepared at 400 °C can be reduced to 3.96 × 10⁻⁷ m²KW⁻¹. Our work provides important experimental data and theoretical basis for optimizing the interlayer between thermoelectric materials and electrodes, and improving energy conversion efficiency of thermoelectric devices.