LAUSR

Abstract Recently, fabrication of high-efficiency miniature thermoelectric devices with thin films have attracted great attention. ZnSb based thin films have been widely studied due to its advantages of earth-abundance, eco-friendly and excellent electron transport properties. However, its thermoelectric performance at room-temperature is still low which extremely restricts its application. In this work, we report a high power factor of 6.2 μWcm-1K-2 and a record high ZT value of 0.35 at room-temperature from the non-stoichiometric ZnSb based thin film, fabricated by a facile magnetron co-sputtering technique. Extensive characterizations reveal that all the prepared films have primary ZnSb phase with well crystallinity, leading to high electrical conductivity. Meanwhile, the carrier concentration is optimized with Zn addition, which contributes to high Seebeck coefficient, resulting in a decent power factor. Simultaneously, the Zn-rich films also show nanopores, Zn-rich nanophases and Zn4Sb3 nano inclusions. These induced nano-structures can enhance the scattering of medium- and long-wavelength phonons, resulting in reduction of lattice thermal conductivity. This work demonstrates that rational nano-structure manipulations can achieve high performance in ZnSb thin films, which possess potential applications for the fabrication of miniature thermoelectric devices.