Assembly of one-dimensional nanorods into Bi_2S_3 films with enhanced thermoelectric transport properties

摘要

Bismuth sulfide thin films have been assembled by cross-linkage nanorods on surface-functionalized Si substrate with self-assembled monolayers. Results of transmission electron microscopy and electron diffraction revealed that highly crystalline Bi_2S_3 nanorods grow along c-axis direction. Electrical transport properties including resistivity (0.02 Ω cm), thermopower (-755 μV K~(-1)), and carrier mobilities (1100 cm~2 V~(-1) s~(-1)) of the Bi_2S_3 films at 300 K are found superior to those of previously reported Bi_2S_3 samples. The Bi_2S_3 films exhibit a maximum thermoelectric power factor (3.97 X 10~(-3) W m~(-1) K~(-2)) at 450 K. The enhancement of thermoelectric properties mainly originates from highly crystalline and oriented nanostructures embedded in the Bi_2S_3 films.