Effect of texture on the structural and transport properties of Sb-doped Mg2Si thin films

With the ever increasing energy demand, the need for miniaturized thermoelectric (TE) devices that minimize energy waste is becoming urgent. In this context, the use of thin film-based devices is a promising strategy provided that suitable materials with appropriate properties are developed. Here, for applications at temperatures ranging from 500 K to 850 K, the TE properties of the Mg2Si compound are investigated after its deposition as thin film by microwave plasma-assisted co-sputtering method. The effects of doping the Mg2Si films with different Sb contents and of the deposition temperature are assessed. Structural characterization shows that the films grown at room temperature exhibit a larger degree of texture and strains compared to those deposited at 463 K. Furthermore, the TE properties (electrical conductivity, Seebeck coefficient, thermal conductivity) are affected in a different way by the deposition temperature, resulting eventually in a higher power factor (based on in-plane characteristics) and higher thermal conductivity (measured out-of-plane) for RT depositions.