Zinc antimonide thin films prepared by ion beam sputtering deposition using ternary layers annealing method

Highlights: • Zn–Sb thin film was synthesized by using ternary layers annealing method. • Zn composition can be effectively controlled after heat treatment by using this approach. • Thin film with Zn4Sb3 as secondary phase has highest power factor at 300 °C. - Abstract: The antimonide and zinc thin films were alternately deposited on BK7 glass substrates to form the "Sb–Zn–Sb" ternary layers by ion beam sputter deposition. The composition of Zn was controlled by changing the sputtering time of zinc at the deposition process. After that, the deposited samples were annealed at 400 °C for 1 h and zinc antimonide thermoelectric thin films with various Zn content were obtained. The influence of the Zn composition on the microstructure, surface morphology and thermoelectric properties of the thin films was systematically investigated. X-ray diffraction results show that the prepared thin film gradually transforms from single ZnSb phase to mixed phase with increasing Zn sputtering time. The sample with the Zn composition of 40% has the highest power factor at room-temperature. An optimal power factor of 1.29 × 10−3 W m−1 K−2 at the temperature of 300 °C was obtained at zinc antimonide thin films with the Zn content of 67%, which possesses a Seebeck coefficient of 188 μV K−1 and a resistivity of 2.75 × 10−5 Ω m