Fig. 8.

a Schematic illustrations of the formation mechanism of the Bi₂Te₃ NWs via a template-assisted solution phase process. b Schematic of tellurium NW formed in the first step and tellurium–bismuth telluride heterostructure after adding bismuth precursor in the second step. c TEM image of the Te–Bi₂Te₃ heterostructured NWs. d Schematic diagram and corresponding TEM images (scale bar: 5 nm) of phase evolution from pristine CdS NW to CdS/Cu₂S core–shell NW, and eventually to CdS/Cu₂S superlattice NW. Temperature dependence of e thermopower and f power factor of Cu₂S nanowire, CdS/Cu₂S core–shell nanowires (C–S) and CdS/Cu₂S superlattice nanowires (SL). Adapted with permission from Refs. [115, 120, 121]