Synthesis and Characterization of Bi2Te3 Nanostructured Thin Films

Thin films of Bi2Te3 were obtained using vacuum evaporation and inert gas evaporation techniques. To study the effect of nanocrystallite size on thermal and electrical properties, deposition temperature and gas pressure were varied and thin films of Bi2Te3 having different crystallite sizes ranging from 7-20 nm were obtained. X-ray Diffraction and scanning electron microscopic studies were carried out to determine phase, crystallite size, strain and surface morphology of nanocrystalline films. Effect of nanocrystallite size on electron transport and thermal properties of Bi2Te3 thin films was studied using Hall effect and Harman's four probe methods. Calculated ZT values were correlated with the carrier concentration, carrier mobility and electrical conductivity of Bi2Te3 thin films. This study shows that strain may influence the electron transport and thermoelectric properties of Bi2Te3 films along with nanocrystallite size.