Annealing effects on the thermoelectric properties of silver-doped bismuth telluride thin films

• The thermal co-evaporation method was successfully employed for the preparation of the Ag doped Bi2Te3 thermoelectric thin films on SiO2/Si substrates with low cost.
• The optimized power factor of 2.16 μW/cm · K2 was obtained for Ag doped Bi2Te3 thin film annealed at 250 °C for 30 min.

The structures and thermoelectric properties of n-type silver-doped Bi2Te3 thin films on SiO2/Si substrates using thermal co-evaporation method were reported. Annealing effects on the thermoelectric properties of thin films were also investigated in the temperature range 100 to 250 °C under nitrogen atmosphere. The crystalline structures and morphologies were examined by X-ray diffraction and field emission scanning electron microscope. The thermoelectric properties of thin films were determined by Seebeck coefficients and electrical conductivity measurements. The results showed that as the thin film is annealed at 250 °C, the Seebeck coefficient and electrical conductivity of − 47.04 μV/K and 976.13 S · cm− 1 can be obtained, respectively, which resulted in an optimum power factor of about 2.16 μW/cm · K2.

The figure shows the power factors obtained for the Ag doped Bi2Te3 thin films annealed at various temperatures for 30 min under N2 atmosphere. The optimum power factor of 4.89 μW/cm·K2 was obtained in this experiment, which is achieved by the 250 °C and 30 min annealing.Figure optionsDownload as PowerPoint slide