Enhanced thermoelectric performance of SnTe thin film through designing oriented nanopillar structure

Highlights: • SnTe thermoelectric film with oriented nanopillar structure is designed and fabricated. • SnTe film shows a highly preferential growth along (222) direction. • The special structure facilitates electrons' transport while scatter the phonons. • SnTe film with highly oriented growth shows enhanced thermoelectric performance. • An effective method is provided with interface engineering for thermoelectric film. SnTe, an ideal lead-free substitute of PbTe, recently has attracted much attention for thermoelectric heat to electricity generation. Previous reports mainly focused on band engineering and all-scale phonon scattering for enhancing the thermoelectric performance of bulk SnTe. Herein, we adopt strategy of interface engineering to design oriented nanopillar structure in SnTe film via one-step thermal evaporation method. The analysis of the electrical and thermal properties illustrates that the SnTe film with highly oriented growth shows enhanced thermoelectric performance. The excellent properties are mainly attributed to the special nanopillar structure, which may facilitate the electrons' transport while significantly scatter the phonons. The maximum power factor of 19.8 μW cm⁻¹ K⁻² and the thermal conductivity of 3.54 W m⁻¹ K⁻¹ are obtained. This work provides a promising approach to enhance the thermoelectric performance of SnTe film, which can be easily extended to other thermoelectric films.