Study On Preparation And Properties Of ZnSb Based Thermoelectric Thin Films

In this study,the low-dimensional and doping methods were simultaneously applied to ZnSb-based thermoelectric materials in order to improve the thermoelectric properties of ZnSb-based materials.ZnSb thin film was fabricated by RF magnetron sputtering of Zn4Sb3 binary target.The effects of sputtering power,vacuum annealing temperature and annealing time on the properties of ZnSb thin films were investigated.Cu and Ag doping was achieved by alternate sputtering deposition of Zn4Sb3 binary target and Cu single target and Ag single target respectively,followed by vacuum homogenization annealing(Cu,Ag single target using DC magnetic Thin films were fabricated by scanning electron microscopy,X-ray diffractometry,Hall-effect tester,thin-film Seebeck coefficient measurement system and conductivity test.The results show that the performance of ZnSb-based thin films can be controlled by the sputtering method.Instrument and so on.The optimal sputtering power of ZnSb thin films is 50 W,and the optimum annealing temperature and annealing time are 300 ? and 1 h,respectively,under the experimental conditions.The results of SEM and XRD showed that the atomic ratio of Zn/Sb was 1:1,and Cu and Ag were evenly distributed in the films.The doping changes the surface morphology of the films,doped ZnSb-based thermoelectric thin films showed that Cu2Sb,Cu10Sb3 and Zn4Sb3 appeared three new phases in the samples with increasing Cu element contents,and the Ag After doping with Ag atom,the surface of the sample film is more compact and homogeneous,and two new phases,Zn4Sb3 and Ag3Sb,appear in the sample.The results show that the Hall coefficient of ZnSb thin films and Cu-doped ZnSb-based thermoelectric thin films are all positive,indicating that the films are P-type semiconductor thin films;Ag-doped ZnSb-based thermoelectric thin films are P type.The carrier concentration and conductivity of the doped samples increase to a certain extent,and the new material formed after doping plays a significant role in improving the electrical properties of the films.The Seebeck coefficient of Cu doped samples decreases with the increase of Cu doping content,and decreases with the increase of test temperature.The Seebeck coefficient of Cu doping samples is mainly due to the increase of doping concentration The increase of the carrier concentration and the improvement of the crystallinity also increase the electrical conductivity of the films doped with Cu.The Seebeck coefficient of Ag doped samples decreases with the increase of Ag doping.The temperature increases slowly and then slowly.The results show that Ag doping is better than Cu doping.The results of the first-principles calculations show that Cu and Ag doping can effectively improve the carrier concentration and conductivity of the ZnSb-based material.The main reason is that the Fermi surface of Zn4Sb3 is deep into valence band,And Cu2Sb,Cu10Sb3 and Ag3Sb phases all exhibit strong metallic properties.These factors increase the carrier concentration and conductivity of the films.The simulation results are in good agreement with the experimental results.