Synthesis Of Bi₂Te₃-based Nanopowders By VAPE And Deposition Of Bi Thin Film By FE Method

Thermoelectric material is a functional material that can be used to convert thermal energy into electrical energy directly with carriers. It has a long performance life and good stability and is good to environment. So it has been used in many fields, especially in thermoelectric power and cooling for electric devices. But its low thermoelectric figure of merit restricts its applications. The improvement of the thermoelectric figure of merit has become a hot spot of research. With the development of nanotechnology and related thermoelectric theory, we can solve the problem on the basis of novel syntheses method or low dimension material. Vacuum arc plasma evaporation (VAPE) is a commonly used method in preparing elementary substance, nitride, oxide, carbide and some other nanopowders, and a singularly used method in preparing nanopowders with combination reaction. It has never been used in preparing thermoelectric material nanopowders before. Using VAPE method, we have successfully prepared thermoelectric nanopowders, which has high quality: such as the small, uniform grain size and high purity.Flash evaporation (FE) method has been successfully applied to prepare thermoelectric thin films. It has some advantage over other preparing methods of thin films, like low cost, simple process, uniform composition and grain size. In the first part, the mechanism of thermoelectric effect has been explained. We sum up the progress made in the research of thermoelectric, and then introduce the application in preparing nanomaterials of VAPE and FE, especially thermoelectric materials. In the second part, Bi2Te3 and Sb2Te3 nanopowders were synthesized by VAPE method. The impact of permanents like composition of raw material, arc current and argon pressure was discussed. The syntheses research of pseudo-ternary (BixSb1-x)2Te3 nanopowders was made. In the third part, we mainly discuss the syntheses research of Bi thin film by FE method. The results show that FE method has the advantage of uniform thin film, simple process and low cost over other methods. In the last part, all the experiment results were summed up, the application prospect of VAPE and FE methods were reviewed, and advice for further research work was given.