Fig. 1. SiNWs fabricated by chemical deposition. (a) Schematic of the synthesis of nanowire arrays by the CVD-VLS method^[37]; (b) schematic of the SiNWs thermoelectric generator; (c) SEM image of a device with an integrated heater and silicon microspacers linking nine 10 μm-long nanofiber arrays; (d) SiNWs arrays connected through Si microspacers^[38]

Fig. 2. ZnO nanofibers fabricated by chemical deposition. (a) Top-view of ZnO nanofiber; (b) top-view of ZnO nanofiber coated with ITO; (c) cross-section of the ZnO/CuO heterojunction; (d) schematic diagram of p-CuO TF/n-ZnO NW heterojunction; (e)TEM image of TiO₂ nanofibers; (f) SAD image of TiO₂ nanofibers; (g) TEM image of TiO₂-CoO nanofibers; (h) SAD image of TiO₂-CoO nanofibers^[42]

Fig. 3. PbTe quantum dot fibers fabricated by chemical deposition. (a) Schematic diagram of quantum dot coat deposited on the glass fibers by LPD; (b) SEM image of spherical PbTe quantum dots fibers; (c) TEM image of spherical PbTe quantum dots fibers; (d) relationship between f_ZTof the quantum dot fibers and temperature^[46]; (e) (f) SEM images of cubic PbTe quantum dots fibers; (g) (h) TEM images of cubic PbTe quantum dot fibers^[47]

Fig. 4. Bi_0.5Sb_1.5Te₃ nanofibers fabricated by chemical deposition^[48]. (a) (b) SEM images of the cross-section of Bi_0.5Sb_1.5Te₃ nanofiber arrays grown by direct current electrodeposition and pulse electrodeposition; (c) (d) TEM images and the corresponding SAED patterns of Bi_0.5Sb_1.5Te₃ nanofibers grown by direct current electrodeposition and pulse electrodeposition; (e)-(i) temperature dependence of f_ZT, electrical conductivity, Seebeck coefficient, power factor, and thermal conductivity of Bi_0.5Sb_1.5Te₃ nanofibers grown by direct current electrodeposition and pulse electrodeposition

Fig. 5. Illustration of nanolithography and pulsed laser deposited Nb-STO nanofibers. (a) PMMA coated substrate before EBL; (b) trenches in the PMMA after EBL exposure and photoresist development; (c) template filled with Nb-STO after PLD; (d) nanofibers on the substrate after liftoff of the PMMA photoresist^[50]; (e) schematic of SiNWs over highly doped silicon wafer formed by the metal assisted chemical etching method^[51]

Fig. 6. Structural characterization of porous SiNWs^[51]. (a) Cross-section and top-view SEM images of the etched SSC; (b)-(e) TEM images of various porous SiNWs etched for 60, 120, 180, 240 min; (f)-(i) high-resolution TEM images of various porous SiNWs etched for 60, 120, 180, 240 min

Fig. 7. Composite nanofibers fabricated by electrospinning^[54]. (a) Schematic diagram of electrospinning technology and its Taylor cone; (b) schematic diagram of electrospinning preparation and its synthesis of composite nanofibers

Fig. 8. Composite thermoelectric fiber fabricated by electrospinning^[59]. (a) Schematic of the preparation of La₂CuO₄ composite thermoelectric fibers by electrospinning; (b) SEM image of La₂CuO₄ fibers heated at 500 ℃ for 2 h; (c) relationship of thermoelectric fibers between output voltages and temperature differences

Fig. 9. Micro/nano thermoelectric fibers fabricated by thermal drawing. (a) Schematic of Bi₂Te₃ micro-nano thermoelectric fibers via the MIT method and their surface-interface structure and defects^[66]; (b) schematic of the preparation method of the SnSe micro-nano thermoelectric fibers and their three-dimensional fabric^[69]

Fig. 10. Performance of the micro-nano Bi₂Te₃ fiber core^[66]. (a) SEM image of the p-type Bi₂Te₃ fiber core bonded on the Si test chip; (b) FEM model for simulating the self-heating 3ω method with COMSOL software; (c) variation of V_3ωvalues and temperature oscillation calculated from COMSOL with frequency, variation of electrical resistance and thermoelectric voltage with temperature; (d) schematic of the fiber core bending model; (e) relationship between bending radius and relative resistance; (f) optical microscopy image of a bent Bi₂Te₃ fiber core