Lattice Strain Enhances Thermoelectric Properties in Sb2Te3/Te Heterostructure

An efficient way to improve thermoelectric (TE) performance of a system by adjusting the lattice strain (e.g., dislocation and nano-interface) without changing its composition is reported in this study. By controlling the crystallization and growth of Te nanoparticles, a Sb2Te3/Te heterostructure with enhanced TE properties is obtained. The growth of Te nanoparticles as well as the introduced lattice strain is characterized by X-ray diffraction, Raman, and high-resolution transmission electron microscopy in details. In addition to the low thermal conductivity (kappa ) caused by lattice strain, the resulting stress on the heterostructure may lead to a state near electronic topological transition that enhances the power factor (PF ). As a result, the optimized figure-of-merit of the Sb2Te3/Te heterojunction reaches up to 0.61 at 300 K with PF and kappa of 11.2 mu W cm(-1) K-2 and 0.55 W m(-1) K-1, respectively. This method can also be applied in other heterojunction systems to improve TE properties.