Nanoscale Bi_xTe_3/Sb_2Te_3 multilayer thin film materials for reduced thermal conductivity

摘要

Multilayer thin films were grown sequentially by evaporating solid antimony (Ⅲ) telluride and bismuth (Ⅲ) telluride as thermoelectric (TE) materials. The grown multilayer films have a periodic structure consisting of eleven or thirty-nine alternating thin film layers where each layer is 10 nm thick. Rutherford backscattering spectrometry (RBS) analysis indicates that the deposited antimony telluride films have the desired stoichiometry of Sb_2Te_3 and the bismuth telluride films are Bi_(1.1)Te_(3.0). A 3ω method thermal conductivity measurement system was used to measure the thermal conductivity of the multilayer thin films. 5 MeV Si ion implantation was performed to improve the thermal conductivity of the multilayer thin films. Thermoelectric devices were fabricated with the multilayer thin films for the measurement of the cross-plane thermoelectric voltage and determination of Seebeck coefficient. The nanostructured multilayer thin film materials were found to have lower thermal conductivity than their conventional bulk materials, and Si ion implantation can decrease the thermal conductivity of the multilayer thin films.