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

Novel T-shaped Bi2Te3-Te heteronanojunctions composed of a rhombohedral structured Bi2Te3 nanoplate and a trigonal structured Te nanorod were fabricated by a simple and facile solvothermal method. A unique crystallographic relationship of [2110](Bi2Te3)//[2110](Te) and [0001](Bi2Te3)//[0001](Te) has been observed for this epitaxial growth. Such epitaxial nature between Bi2Te3 nanoplates and Te nanorods is caused by their negligible lattice mismatches in the corresponding atomic planes. The interfaces between Bi2Te3 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.