Effect of Substrate Temperature on the Thermoelectric Properties of the Sb2Te3 Thin Films Deposition by Using Thermal Evaporation Method

The antimony-telluride (Sb2Te3) thermoelectric thin films were prepared on SiO2/Si substrates by thermal evaporation method. The substrate temperature that ranged from room temperature to 150 degrees C was adopted to deposit the Sb2Te3 thin films. The effects of substrate temperature on the microstructures and thermoelectric properties of the Sb2Te3 thin films were investigated. The crystal structure and surface morphology of the Sb2Te3 thin films were characterized by X-ray diffraction analyses and field emission scanning electron microscope observation. The RT-deposited Sb2Te3 thin films showed the amorphous phase. Te and Sb2Te3 phases were coexisted in the Sb2Te3-based thin films as the substrate temperature was higher than room temperature. The average grain sizes of the Sb2Te3-based thin films were 39 nm, 45 nm, 62 nm, 84 nm, and 108 nm, as the substrate temperatures were 50 degrees C, 75 degrees C, 100 degrees C, 125 degrees C, and 150 degrees C, respectively. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature; we had found that they were critically dependent on the substrate temperature.