Improvement of thermoelectric properties by introducing nanostructures into Bi2Te3 thin films

For enhancement of a dimensionless figure of merit (ZT) of Bi₂Te₃ thin films, we carried out a reduction of thermal conductivity (kappa) using artificially introduced crystalline defects during thin film growth. Bi₂Te₃ thin films dispersed CeO₂ nano-dots were deposited on Al₂O₃ (0001) substrates by pulsed laser deposition method. From x-ray diffraction (XRD) patterns, the films were confirmed complete c-axis orientation. The minimum value of kappa in Bi₂Te₃ with ~5 vol.% CeO₂ nano-dots was lower than the half value of kappa on a pure Bi₂Te₃ thin film. The highest value of ZT in the Bi₂Te₃ thin film reached about 2.4 times higher than that in pure Bi₂Te₃ thin film.