Elemental Ratio Controlled Semiconductor Type of Bismuth Telluride Alloy Thin Films

摘要:

通过磁控共溅射的方法制备了Bi2Te3合金薄膜，并通过423~623 K，1 h热处理提高薄膜的结晶程度。随着热处理温度的升高，Te/Bi原子含量比例逐渐减小，这说明在热处理过程中Te元素有一定的挥发，其挥发量随着温度的升高而增加，这使得薄膜的半导体类型由N型转变为P型，同时赛贝克系数也由负值变为正值。另外，热处理导致了晶粒长大，降低了缺陷密度，使得薄膜的电导率和赛贝克系数等热电性能得到提高

Abstract:

Bismuth telluride alloy thin films were prepared on quartz substrates by co-sputtering method and thermally annealed at 423~623 K, for 1 h. It is found that the Te/Bi ratio decreases upon thermal annealing, indicating the loss of Te as a result of evaporation. This leads to the transformation of Bi2Te3 thin films from n-type to p-type, and consequently the change of Seebeck coefficient from the negative value to the positive one. In addition, the grain growth occurs during thermal annealing, in particular, at higher temperature, as a result, both the electrical conductivity and the seebeck coefficient are increased