Nanoporous (00l)-oriented Bi2Te3 nanoplate film for improved thermoelectric performance

Abstract Nanoplates usually synthesized by chemical methods and nanoporous materials have been predicted to have superior thermoelectric properties and have attracted extensive attention. Through a facile process combining chemical and physical methods (including annealing and reaction-engineered solution method), pristine intersected Bi2Te3 nanoplates prepared by molecular beam epitaxial are flattened to (00l)-oriented nanoplates film embedded with controllable nanopores in this paper. A maximum in-plane power factor of 49.1 μW cm−1 K−2 is reached in nanoporous (00l)-oriented Bi2Te3 nanoplates. The corresponding porosity, pore size and pore number of the nanoplate film are 0.6%, 122 nm and 28 per 100 μm2, respectively. The estimated in-plane ZT is larger than 1.2 at 300 K based on measured cross-plane thermal conductivity and anisotropy factor in single crystal. The ZT value is comparable to that of the commercial bulk thermoelectric materials and can be further improved by optimizing the pores’ parameters. This work provides a approach to engineer multifunctional nanoplates film in micro-nano devices.