Bismuth nanowire thermoelectrics

Abstract

Here, we review the current progress in the thermoelectrics of bismuth nanowires, the fundamentals of their advantage and limitation over bulk Bi, and their potential use for enhancing thermoelectric performance.

Reinventing solid state electronics: Harnessing quantum confinement in bismuth thin films

“…As a result, quantum confinement in lowdimensional (2D, 1D) semimetal materials leads to a semimetal-to-semiconductor transition as the physical size of a nanostructure becomes comparable to the Fermi wavelengths of electrons and holes (6). Bulk bismuth has a rhombohedral crystal structure, which can be expressed in terms of a hexagonal unit cell, and is a semimetal with band overlap between the valence and conduction band of 38 meV and 98 meV at 2 K and 300 K, respectively (7)(8)(9)(10). Here, the quantum confinement effect is used to demonstrate that for (111) Bi thin films of thickness less than 6 nm, a 'positive' band gap > 100 meV emerges allowing for the formation of a metal-semiconductor junction between a thick (semimetallic) and thin (semiconducting) region in a single film.…”

Nanobismuth: Fabrication, Optical, and Plasmonic Properties—Emerging Applications

“…By tuning the anodization parameters, the pore diameter and packing density of AAO can be well controlled [67,75]. In such AAO templates, arrays of Bi nanowires were grown by filling the pores by pressurized injection of liquid Bi (the liquid-phase method), by Journal of Nanotechnologyelectrochemical deposition, or by vapor-phase deposition, as shown in Figures 3(b)-3(e) [60,67,68]. Using pressurized injection, most Bi nanowires could be single crystalline along the [202] direction in the hexagonal lattice with a broad diameter tunability range (12-109 nm), but they experience high stress [75].…”

“…e size of these structures covers the range from a few atoms to few microns, which has allowed a wide suitability for studies in various fields including quantum transport, thermoelectricity, topological insulators, giant magnetoresistance, and superconductivity [24,[59][60][61][62]. Such size control is also especially relevant for the fields of plasmonics and nanophotonics, where the working wavelength of the system is closely related to the dimension of the nanostructures.…”

“…ey can be divided into two groups: one is template based, where selected matrices are used to prepare the Bi nanostructures [60,[66][67][68][69][70], and the other is template free. In the latter case, many techniques are used.…”

Observation of anisotropy in thermoelectric properties of individual single-crystalline bismuth nanowires

“…[14][15][16] For nanowires, although it is expected that the anisotropic transport can be observed clearly according to the crystal orientation of the growth direction owing to the one-dimensional carrier transport, systematic investigation is considerably challenging because the crystal orientation of Bi nanowires is limited by the growth method. 17 Single-crystalline Bi nanowires grown using anodic aluminum-oxide templates and the Ulitovsky method were found to be grown along the [101] and [1][2][3][4][5][6][7][8][9][10][11] directions, respectively, in a hexagonal lattice. 18,19 Therefore, the transport properties were measured along only one crystal orientation in each study.…”