Study On Preparation And Propertires Of CoSb₃ Based Thermoelectric Thin Film

Thermoelectric material is a green energy materials, which has important application value and broad application prospects. Skutterudite materialsare considered to be the highest application prospect of the one of medium temperature range thermoelectric material system, which have large Hall mobility, greater conductivity and Seebeck coefficient, based on skutterudite crystal structure and complex cubic structure. Antimony cobalt （CoSb₃）-based thermoelectric materials is researched as one of the most popular skutterudite materials. In recent years, the study of thermoelectric properties of CoSb₃-based thermoelectric materials found thinning and doping can help to improve the thermoelectric properties of CoSb₃-based thermoelectric materials. Therefore, in this paper, the CoSb₃-based thermoelectric films were deposited by the technology of magnetron sputtering. The thermoelectric properties of the deposited thin films are greatly improved by magnetron sputtering and investigating the influence of preparation conditions on microstructure, composition and thermoelectric properties of CoSb₃-based thermoelectric films. The main points of the paper are as follow.CoSb₃ thermoelectric thin films were fabricated by co-sputtering on polyimide （PI） flexible substrate. The influence of different process parameters on the structure and thermoelectric properties was investigated. When the sputtering power of Co target and Sb target is 45 W and 24 W, respectively, the atomic ratio of Co and Sb is close to the stoichiometric 1:3. When the annealing temperature achieves 518 K, the highest power factor of 4.7×10^-5 Wm^-1K^-2 is obtained with the maximum Seebeck coefficient of-35.6 μVK-1 at the measure temperature 353 K.CoSb₃ thermoelectric thin films were prepared by CoSb₃ target using RF magnetron sputtering. The influence of sputtering power and annealing temperature on structural and thermoelectric properties was investigated. The results showed that when the sputtering power is 55 W, the atomic ratio of Co and Sb is close to the stoichiometric 1:3. And appropriate annealing temperature can optimize the crystallin quality of the thin films, with high electrical conductivity and Seebeck coefficient; when the annealing temperature is 518 K, CoSb₃ thin film sample with the sputtering power of 55 W at the test temperature 473 K has the maximum power factor of 1.71×10^-4 Wm^-1K^-2.Based on the above preparation of the CoSb₃ thin film, we continue to study the doped CoSb₃-based thin films. Dopant materials are In, AZO and ZnO. The results showed that:when the In doping time was 60 s, and the test temperature was 443 K, the thermoelectric properties of the In-CoSb₃ film has the maximum power factor, 1.26 × 10^-3 Wm^-1K^-2. When the AZO recombined time is 90 s, the maximum electrical conductivity is 4.2×10⁴ Sm^-1. The crystalline quality of ZnO recombined CoSb₃ thin film is improved, the Seebeck coefficient of ZnO doping CoSb₃ sample at 60 s recombining time is almost linearly upward within the test temperature range, the maximum is-282 μVK^-1, which was a significantly improvement compared to the unrecombined sample; As the result of AZO and ZnO recombining, the thermoelectric properties of AZO and ZnO double-recombined CoSb₃ thin film was further studied, the test results showed that the Seebeck coefficient and electrical conductivity of the AZO and ZnO double-recombined CoSb₃ thin film increased.