Preparation and Thermoelectric Properties of P-Type (Bi0.25Sb0.75)2Te3 Thin Films

P-type (Bi0.25Sb0.75)2Te3 thermoelectric thin films were deposited by flash evaporation method with thickness between 50-400 nm. All of the thin films were annealed in 503 K for one hour. Phase structure of thin films, surface morphology and stoichiometric ratio were characterized via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS). XRD results show that the films of the main diffraction peak and the standard Bi2Te3 and Bi2Sb3 diffraction peak are the same. As-deposited thin film show the (006) plane sharp peak with a preferred orientation. After annealing, it is observed that the (006) plane becomes the most intense peak. Thin films thickness was measured by surface roughometer. Electrical conductivity and Seebeck coefficient of thin films were measured using four-probe method and the Seebeck coefficient measurement system at room temperature, respectively. The results show that the thin films are p-type conduction. Effects of the thin films thickness on electrical conductivity and Seebeck coefficient were investigated.