Thermoelectric Properties of n-Type Bismuth Telluride (Bi2Te3) Thin Films Prepared by RF Sputtering

초록

We report electrical and thermoelectric (TE) properties of sputtered n-type Bi2Te3 thin films with the effect of post-annealing at temperature ranging from 20 to 250 degrees C under Ar atmosphere. With increasing annealing temperatures from 20 to 250 degrees C, electrical and TE properties of Bi2Te3 thin films were slowly improved. However, we found that there is no remarkable improvement in the electrical and TE properties with heat treatment. For the Bi2Te3 thin films annealed at 150 degrees C, where the electrical and TE properties reached the highest values, the electrical conductivity, Seebeck coefficient, mobility, carrier concentration, power factor, thermal conductivity, and figure-of-merit, ZT were determined to be similar to 2.5x 10(3) Scm(-1), -34 mu V/K, similar to 7.2 cm(2)V.s, similar to 2.5x 10(21) cm(-3), similar to 2.9 mu W/K(2)cm, similar to 0.35 W/m . K, and similar to 0.23, respectively. Our results clearly indicate that even as-grown Bi2Te3 thin films can be used for the TE devices applications, especially wearable devices, in which further heat treatment is not allowed for the improvement of the film quality.

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