T-Shaped Bi2Te3–Te Heteronanojunctions: Epitaxial Growth, Structural Modeling, and Thermoelectric Properties

Novel T-shaped Bi 2 Te 3 –Te heteronanojunctions composed of a rhombohedral structured Bi 2 Te 3 nanoplate and a trigonal structured Te nanorod were fabricated by a simple and facile solvothermal method. A unique crystallographic relationship of [21̅1̅0] Bi 2 Te 3 //[21̅1̅0] Te and [0001] Bi 2 Te 3 //[0001] Te has been observed for this epitaxial growth. Such epitaxial nature between Bi 2 Te 3 nanoplates and Te nanorods is caused by their negligible lattice mismatches in the corresponding atomic planes. The interfaces between Bi 2 Te 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.