T-Shaped Bi_2Te_3–Te Heteronanojunctions: Epitaxial Growth, Structural Modeling, and Thermoelectric Properties

Novel T-shaped Bi_2Te_3–Te heteronanojunctions composed of a rhombohedral structured Bi_2Te_3 nanoplate and a trigonal structured Te nanorod were fabricated by a simple and facile solvothermal method. A unique crystallographic relationship of [21̅1̅0]_(Bi2Te3)//[21̅1̅0]_(Te) and [0001]_(Bi2Te3)//[0001]_(Te) has been observed for this epitaxial growth. Such epitaxial nature between Bi_2Te_3 nanoplates and Te nanorods is caused by their negligible lattice mismatches in the corresponding atomic planes. The interfaces between Bi_2Te_3 nanoplates and Te nanorods lead to a low thermal conductivity in these heteronanojunctions, so that a promising figure of merit (ZT) value is obtained (0.73 ± 0.04 at 320 K). This study provides a new method and opportunity to engineer heteronanojunctions for high-efficiency thermoelectric devices for power generation