めっき浴温度を制御して成膜したビスマステルル薄膜の構造および熱電特性

抄録

To improve the thermoelectric performance of bismuth telluride (Bi₂Te₃) thin film using electrodeposition, we investigated the effect of electrolyte temperature ranging from 10°C to 70°C. The thermoelectric properties including electrical conductivity, Seebeck coefficient and power factor were measured at room temperature in the in-plane direction. The structural properties were examined by scanning electron microscope and X-ray diffraction analysis. The maximum power factor of 1.3 μW/(K²･cm) was exhibited at a electrolyte temperate of 20°C. For further increasing the electrolyte temperature, the power factor linearly decreased because both the electrical conductivity and Seebeck coefficient decreased. The surface structure of the Bi₂Te₃ thin films greatly changed when the electrolyte temperature was changed. The Bi₂Te₃ thin films at lower electrolyte temperature (T < 30°C) exhibited dense structure while the thin films at higher electrolyte temperature (T > 50°C) exhibited dendrite structure and many deep apertures which caused a decrease in the thermoelectric performance.