Abstract
In this study, the Bi/Te multilayer thin films were deposited on SiO2/Si substrate by magnetron sputter deposition method, and transformed into Bi-Te compound by thermal treatment. Effect of relative Bi/Te composite on the thermoelectric properties of annealed Bi/Te multilayer thin films was investigated. It has been observed that the interdiffusion between Bi and Te was improved and the reaction time was shortened by using the Bi/Te multilayer structure. According to the variation of interdiffusivity with annealing time, it is speculated that the formation of Bi2Te3 may retard the interdiffusion between Bi and Te. During short annealing time, the oscillatory behavior of transport properties was attributed to quantum size effects. The Bi/Te multilayer thin films shows a maximum Seebeck coefficient of -345μV/K, that is much higher than that of bulk Bi2Te3 (-240 μV/K). We can control Te at.% of thin films by changing the sputtering time ratio of Bi to Te. After long time annealing, Seebeck coefficient changes from positive to negative at a composition around 60 at.% Te. The maximum values of positive and negative were found to be +211μV/K and -201.3μV/K, respectively. Moreover, the cross-plane thermal conductivity of the Bi/Te multilayer thin films was measured to be 0.62W/m-K by the 3ω method.