Bi2Te3 nanoplates’ selective growth on different interface for enhancing thermoelectric performance

Bi2Te3, a typical thermoelectric (TE) material as well as topological insulator, exhibits anisotropy characteristics duo to its layered structure. (00l)-oriented Bi2Te3 reported with good TE properties in ab-plane, is not the best choice for “π”-type nano-micro TE devices. Bi2Te3 nanoplates’ growth behavior as well as their corresponding TE properties was modulated on different substrates (Si (111), H-terminated Si (111) and glass) by molecular beam epitaxy (MBE) in this paper. The interfaces between Bi2Te3 and substrate play an important role in Bi2Te3 nanoplates’ morphology, so as the related TE properties. The intersected nanoplates which possess higher density grain boundaries compared with the stacked ones, filter the low energy carriers and enhance phonon scattering. Thus, increased Seebeck coefficient was achieved and predictable reduction of thermal conductivity by using intersected nanoplates. Moreover, the ratio of intersected/stacked Bi2Te3 nanoplates as well as their size can be properly contr...